Keynote/Invited Speakers

01 I. Emerging Materials for Rechargeable Batteries

Keynote Speakers

Anton Van der Ven

University of california, santa babara

TBD

CV

Yoon Suk Lee

Hong Kong PolyTechnic University

Recycling of Waste Lithium-Ion Batteries - An Urban Mine of Transition Metals

Abstract

Recycling of Waste Lithium-Ion Batteries - An Urban Mine of Transition Metals

Lawrence Yoon Suk Lee*1, Zhen Li1

1The Hong Kong Polytechnic University

The shift in the energy paradigm towards renewable energy has driven the growing adoption of lithium-ion batteries (LIBs) for electric vehicles and energy storage grids. This rapid growth in the LIB market has resulted in an increasing volume of spent batteries, presenting both waste management challenges and opportunities to recover valuable metals.
In this talk, two innovative strategies to reclaim Li and other transition metals from waste LIBs will be discussed, which avoid the energy-intensive and inefficient steps in conventional recycling methods. The first approach involves co-pyrolysis of spent LIBs and benzene-containing waste polymers. Using a sealed reactor with two compartments, the decomposed polymers can extract Li and transition metals from LIB cathodes without emitting toxic benzene-based gases, achieving recovery rates exceeding 98 %. This method is further extended to utilize waste biomass, allowing for the recovery of Li and the production of an active water remediation catalyst capable of degrading ciprofloxacin. The second strategy demonstrates the direct and cross-domain reuse of materials from waste LIBs through a top-down approach. A single-atomic catalytic system upcycled from a LiFePO4 cathode exhibits excellent activity, selectivity, and stability for the oxygen reduction reaction, showcasing its potential in practical energy conversion devices such as ammonia fuel cells and zinc-air batteries. These strategies highlight the potential of waste LIBs as an "urban mine" for the reclamation of critical transition metals, addressing both the environmental concerns and the growing demand for these valuable resources.

Keywords : recycle; LIB; cross-domain upcycle; single-atom catalyst

Corresponding Author : Lawrence Yoon Suk Lee (lawrence.ys.lee@polyu.edu.hk)

CV

Invited Speakers

Name	Affiliation	Title	Abstract	CV
Youngmin Ko	Sungkyunkwan University	Interphase design by localized super-concentrated electrolytes for high-voltage and high-power lithium metal batteries	Abstract Interphase design by localized super-concentrated electrolytes for high-voltage and high-power lithium metal batteries Youngmin Ko2, Brett Helms*1 1Lawrence Berkeley National Laboratory, 2Sungkyunkwan University Batteries used in electric aircraft must deliver high-power on take-off and landing, providing in stride the ability to recharge at high voltage to make full use of the cathode capacity. Impedance rise associated with electrode–electrolyte interphases remains problematic with conventional electrolytes, resulting in unacceptable power fade. This is exacerbated when recharging cells at high voltage, which is where interphase generation remains poorly controlled. To address these issues, electrolyte design for high-voltage and high-power batteries should emphasize control over the interphase growth contributing to the impedance rise during charge. To this end, we will describe our recent efforts to alter the activity of various electrolyte components at electrode–electrolyte interfaces, granting access to exquisite control over interphase chemistry. Key to our success is the exploitation of ion clustering in locally super-concentrated electrolytes (LSCEs), which produces aggregates with intrinsically different reactivity than solvated species and from which new interphasial chemistries may be produced in-situ. We find in top-performing compositions that interphase stability is most affected by the activity of ethereal solvents in the formulations, particularly at high voltage, and that it is possible to design additives that suppress solvent activity. Li/NMC811 cells cycled with de-novo designed LSCEs maintain 60% of their initial discharge capacity after 500 cycles with 4 C discharge rate at charge cut-off voltage of 4.35 V, outperforming most reported electrolytes for Li metal batteries. Keywords : Localized superconcentrated electrolytes, lithium metal batteries, interphase, high power Corresponding Author : Brett Helms (bahelms@lbl.gov)	CV
Taehoon Kim	Korea Institute of Materials Science	A New Current Collector Material for Lightweight Lithium-Ion Batteries: Direct-Spun CNT Fibers	Abstract A New Current Collector Material for Lightweight Lithium-Ion Batteries: Direct-Spun CNT Fibers Taehoon Kim*1, Kyunbae Lee1, Yeonsu Jung1 1Korea Institute of Materials Science To enhance the driving range of electric vehicles, various efforts are being made to increase the energy storage density of lithium secondary batteries. Notable approaches include developing new cathode materials with higher nickel content, creating anode materials using silicon, utilizing thinner separators, and reducing the amount of binders and conductive agents. Current collectors, which account for over 12 wt% of the battery's mass, do not contribute to energy storage. Therefore, replacing them with thinner and lighter materials is desirable. Although thinner copper and aluminum films are being used, further reduction in thickness is challenging due to the need for maintaining essential mechanical properties during battery processing. In this presentation, instead of reducing the thickness of metal films, we aimed to achieve lightweight lithium-ion batteries by utilizing carbon nanotube (CNT) fibers as next-generation current collectors. These CNT fibers possess high strength and electrical conductivity while maintaining a density of less than 1 g/cm³. We fabricated films using CNT fibers to replace both the aluminum cathode current collector and the copper anode current collector. To evaluate their feasibility, we sequentially assembled coin cell-based half-cells and pouch cell-based full cells. The CNT fiber-based current collectors were not only lightweight but also exhibited an additional advantage of enabling high-rate charge and discharge. With further advancements in mass production and process optimization, CNT fiber-based current collectors are expected to play a significant role in the development of next-generation secondary batteries. Keywords : CNT Fiber, Current collector, Lightweight Corresponding Author : Taehoon Kim (tkim67@kims.re.kr)	CV
Jun Young Cheong	University of Glasgow	Multifaceted Applications of Electrospinning in Rechargeable Batteries	Abstract Multifaceted Applications of Electrospinning in Rechargeable Batteries Jun Young Cheong*1 1University of Glasgow Synthesis and fabrication of rationally designed and tailored materials are highly critical, as they contribute to different physicochemical properties and performances. Recently, a lot of studies have been carried out for the nanostructured materials because they offer some significant advantages in i) high surface area & ii) surface to volume ratio, which can be an important aspect for studying in various applications. Electrospinning is one of the widely used technologies to synthesize not only one-dimensional nanofiber (one-dimensional) but can also make this in the form of membrane (two-dimensional), and electrospun sponges (three-dimensional). In this presentation, the introduction to the electrospinning technologies as well as its flexibility in tuning the composition and morphology of the materials will be presented, with examples of research works. Keywords : Electrospinning, Rechargeable, Nanomaterials, Batteries Corresponding Author : Jun Young Cheong (JunYoung.Cheong@glasgow.ac.uk)	CV
Jun-woo Park	Korea Electrotechnology Research Institute	Development Trends of High-Energy-Density Lithium-Sulfur Batteries for Future Aerospace Transportation	Abstract Development Trends of High-Energy-Density Lithium-Sulfur Batteries for Future Aerospace Transportation Jun-Woo Park*1, Junyoung Heo1, Hawon Gu1, Junghwan Sung2, Dong-Hee Kim1, You-Jin Lee1, Hae-Young Choi2, Doohun Kim1 1Korea Electrotechnology Research Institute, Korea National University of Science and Technology, 2Korea Electrotechnology Research Institute Lithium-sulfur (Li-S) batteries have emerged as a promising energy storage solution for future aerospace transportation owing to their high energy density, lightweight nature, and cost-effectiveness. Compared to conventional lithium-ion batteries, Li-S systems offer significantly higher theoretical capacities and environmental benefits, making them ideal for applications where weight and energy efficiency are critical. Despite these advantages, several challenges hinder the widespread adoption of Li-S batteries. Major issues include the intrinsic low electrical conductivity of sulfur, the polysulfide shuttle effect that leads to rapid capacity degradation, and substantial volume changes during charge-discharge cycles. These factors collectively limit the cycle life and overall performance of Li-S batteries, necessitating innovative solutions for their effective implementation. To address these challenges, extensive research efforts have been devoted to optimizing both materials and cell architectures. In our work, we focus on two key strategies: the development of freestanding cathodes and the incorporation of functional interlayers. Freestanding cathodes eliminate the need for heavy current collectors, thus reducing overall weight and enhancing energy density. Meanwhile, the integration of a functional interlayer acts as a barrier to mitigate the diffusion of polysulfides, significantly improving cycle stability and prolonging battery life. This abstract provides an overview of the current development trends in Li-S battery technology, highlighting the critical need for advanced materials solutions. The targeted approaches of freestanding cathode fabrication and functional interlayer integration represent promising pathways toward overcoming the inherent limitations of Li-S systems, paving the way for their practical application in the next generation of aerospace transportation. Keywords : Lithium-sulfur batteries, Freestanding electrode, Functional interlayer Corresponding Author : Jun-Woo Park (parkjw@keri.re.kr)	CV
Young-Woon Byeon	Korea Institute of Science and Technology	Nanoscale Surface Structural Evolution in Battery Materials: A Multi-Interface Analysis Centered on PED-Based 4D-STEM	Abstract Nanoscale Surface Structural Evolution in Battery Materials: A Multi-Interface Analysis Centered on PED-Based 4D-STEM Young-Woon Byeon*1, Jae-Pyoung Ahn1, Hong-Kyu Kim1, Hyoung-Cheoul Shim2, ChangIn Kim1 1Advanced Analysis and Data Center, Korea Institute of Science and Technology, 2School of Materials Science and Semiconductor Engineering, University of Ulsan With the rapid expansion of the electric vehicle market, ensuring the longevity and reliability of lithium-based battery materials has become a critical challenge. Understanding structural degradation phenomena occurring at the electrode surface and interface is essential for the rational design of next-generation energy storage materials. This work presents a comprehensive multi-system investigation of surface degradation behaviors across different electrode environments using advanced electron diffraction and spectroscopy techniques. Central to our approach is precession electron diffraction (PED)-based four-dimensional scanning transmission electron microscopy (4D-STEM), which enables the quantitative mapping of strain–phase correlation at the sub-10 nm scale. By applying statistical analysis to PED-4D datasets, we visualized the emergence and distribution of metastable phases and local degradation domains that develop during electrochemical cycling, particularly in layered NCM cathode systems. In addition, previously published results on interfacial degradation and recovery phenomena in lithium metal anodes and composite cathodes of sulfide-based solid-state systems are briefly overviewed. Looking forward, low-dose electron beam techniques, cryo-environmental structural analysis, and advanced data processing algorithms for complex multiphase systems will be essential to further improve the analytical resolution. These approaches will be critical to detecting early-stage degradation signatures and establishing a dynamic, feedback-driven loop between real-time interfacial analysis and material design strategies. Together, these findings underscore the potential of PED-based 4D-STEM as a unifying platform for quantifying interfacial dynamics, offering critical insights for building a robust feedback loop between nanoscale analysis and high-performance battery material design. Keywords : TEM, Precession Electron Diffraction (PED), Correlation Analysis, Data-driven Materials Analysis Corresponding Author : Young-Woon Byeon (youngwoonbyeon@gmail.com)	CV
Masayoshi Watanabe	Yokohama National University	Soft Matter Electrolytes for Next Generation Batteries	Abstract Soft Matter Electrolytes for Next Generation Batteries Masayoshi Watanabe*1 1Yokohama National University Soft matter electrolytes, including ionic liquids, solvate ionic liquids, dense ionic fluids, ion-gels (polymer gel electrolytes containing ionic liquids), and solid polymer electrolytes, bridge the gap between conventional liquid electrolytes and solid-state electrolytes. This presentation explores the ion transport properties and interfacial charge transfer processes of soft matter electrolytes, along with their applications in electrochemical devices. In recent years, unusual transport behaviors and interfacial electrochemical processes—unobserved in conventional organic electrolytes—have been reported. These unique properties stem from distinctive solvation structures involving cations, anions, and solvents, including polymer segments. Such findings offer new opportunities for innovative electrolyte design. The development of novel electrolyte materials is crucial for advancing next-generation batteries. Soft matter electrolytes are expected to play a key role in this progress by enhancing safety, enabling stable and facile electrode–electrolyte interface formation, and offering cost-effective manufacturing solutions. References 1) M. Watanabe, M. L. Thomas, S. Zhang, K. Ueno, T. Yasuda, K. Dokko, Chem. Rev. 117, 7190-7239 (2017). 2) M. Watanabe, K. Dokko, K. Ueno, M. L. Thomas, Bull. Chem. Soc. Jpn., 91, 1660-1682 (2018). 3) M. Watanabe, Bull. Chem. Soc. Jpn., 94, 2739-2769 (2021). 4) Y. Ugata, K. Shigenobu, R. Tatara, K. Ueno, M. Watanabe, K. Dokko, Phys. Chem. Chem. Phys., 23, 21419-21436 (2021). Keywords : Soft Matter Electrolyte, Ionic Liquid, Solvate Ionic Liquid, Dense Ionic Fluid, Ion-Gel, Solid Polymer Electrolyte Corresponding Author : Masayoshi Watanabe (mwatanab@ynu.ac.jp)	CV
Jinkwang Hwang	Kyoto University	Oxygen-Powered Preparation of FePO4 and Its Application in Metal Batteries	Abstract Oxygen-Powered Preparation of FePO4 and Its Application in Metal Batteries Jinkwang Hwang*1, Fumiyasu Nozaki1, Shaoning Zhang1, Kazuhiko Matsumoto1 1Kyoto University Triphylite (olivine) NaFePO4 presents a promising option for sodium secondary batteries due to its abundance of constituent elements and high energy density, making it suitable for sustainable energy storage.[1-2] However, its direct synthesis is challenged by thermal metastability.[3] This presentation introduces an oxygen-powered method for the sustainable production of heterosite FePO4, the desodiated variant of triphylite NaFePO4, sourced from LiFePO4. In this process, oxygen serves as the oxidizing agent for the delithiation of LiFePO4 within a closed-loop system. During delithiation, lithium is recovered as lithium acetate, enabling the repeated synthesis of LiFePO4 from the recovered lithium acetate. This lithium recycling method has been established to facilitate cost-effective production of FePO4.[4] Additionally, we propose charged-state lean metal batteries configuration designed to enhance the cyclability of metal-free batteries while retaining high energy density, addressing a key challenge in metal batteries. References [1] S.-M. Oh, S.-T. Myung, J. Hassoun, B. Scrosati and Y.-K. Sun, Electrochem. Comm., 2012, 22, 149. [2] W. Tang, X. Song, Y. Du, C. Peng, M. Lin, S. Xi, B. Tian, J. Zheng, Y. Wu, F. Pan and K. P. Loh, J. Mater. Chem. A, 2016, 4, 4882. [3] M. Avdeev, Z. Mohamed, C. D. Ling, J. Lu, M. Tamaru, A. Yamada and P. Barpanda, Inorg. Chem., 2013, 52, 8685. [4] F. Nozaki, S. Zhang, M. H. Petersen, J. Hwang, J. H. Chang, J. M. G.-Lastra, K. Matsumoto, Energy Envron. Sci., 2025, 18, 1408. Keywords : sodium batteries, metal batteries, FePO4, olivine Corresponding Author : Jinkwang Hwang (hwang.jinkwang.5c@kyoto-u.ac.jp)	CV
Jinhye Bae	University of California San Diego & Chung-Ang University	Multifunctional Hydrogels and Their Manufacturing for Flexible Batteries	Abstract Multifunctional Hydrogels and Their Manufacturing for Flexible Batteries Jinhye Bae*1 1Chung-Ang University & University of California San Diego Stimuli-responsive hydrogels have emerged as versatile materials capable of sensing and adapting to environmental stimuli, making them ideal for dynamic applications in soft electronics, robotics, and bioengineering. This talk will present recent advances in the design and fabrication of multifunctional hydrogel systems with programmable structural and functional properties. By incorporating responsive polymers and functional additives, these hydrogels can undergo controlled shape morphing and functional transitions under external stimuli such as temperature, pH, or light. A central focus will be on the use of extrusion-based 3D printing to precisely control the spatial organization and performance of hydrogel materials. This fabrication approach enables the creation of architected structures with tunable mechanical, chemical, and responsive properties. Complex geometries and multi-material compositions can be integrated at multiple length scales to support localized actuation and reconfigurable behavior. The talk will highlight recent developments in printable ink formulations, structure–function relationships, and dynamic morphologies that expand the capabilities of active hydrogel-based systems. Finally, the application of this hydrogel platform to energy storage will be briefly discussed. By leveraging the intrinsic ionic conductivity and deformability of hydrogels, printed hydrogel electrolytes could be useful for flexible battery systems to maintain performance under mechanical and environmental stress. Keywords : hydrogels, flexible batteries, 3D printing Corresponding Author : Jinhye Bae (j3bae@ucsd.edu)	CV
Hyun Woo Kim	Gyeongsang National University	TBD		CV
Jong-Hwa Hong	Korea Institute of Materials Science	Numerical Simulation as a Key Driver in Battery Cell Can Manufacturing Innovations	Abstract Numerical Simulation as a Key Driver in Battery Cell Can Manufacturing Innovations Jong-Hwa Hong*1 1Korea Institute of Materials Science The EV fire that occurred in Incheon (Cheongna), Korea, in August 2024 highlighted significant safety concerns. It was later revealed that the fire was caused by pouch battery. Pouch battery uses a thin aluminum laminate film as their outer casing, making them structurally weaker than prismatic and cylindrical batteries and more vulnerable to external shocks and internal pressure changes. Additionally, the absence of a metal can makes heat dissipation more challenging, increasing the risk of localized heat accumulation and thermal runaway. As a result, the adoption of prismatic and cylindrical batteries in EVs has rapidly increased in recent years. However, the shapes of prismatic and cylindrical batteries have been rapidly evolving in recent years, requiring adaptive responses to new manufacturing processes. A notable example is Tesla's transition from conventional 18650 and 21700 cells to 4680 cells. As a powerful tool, numerical simulation plays a crucial role in adapting to these rapid changes by significantly reducing costs and time. The presentation introduces process development cases utilizing numerical simulation for both prismatic and cylindrical batteries cell cans. In particular, it highlights the development of cylindrical battery cell cans, focusing on the emerging trend of 4680 cell development. This presentation introduces the latest cell can manufacturing processes and the associated technologies. Keywords : Materials processing, Numerical simulation, Battery cell can, Cylindrical type battery, Prismatic type battery Corresponding Author : Jong-Hwa Hong (jhong@kims.re.kr)	CV
Orapa Tamwattana	Khon Kaen University	Leaching Organic SEI by Electrochemical Dissolution at 2-V cutoff Leads to monolithic inorganic SEI and Enhancing Cycle Stability for Anode Free Battery	Abstract Leaching Organic SEI by Electrochemical Dissolution at 2-V cutoff Leads to monolithic inorganic SEI and Enhancing Cycle Stability for Anode Free Battery Orapa Tamwattana3, Hayoung Park2, Jihyeon Kim1, Byunghoon Kim1, Jungwon Park2, Kisuk Kang*1 1Department of Materials Science and Engineering, Research Institute for Advanced Materials, Seoul National University, 2School of Chemical and Biological Engineering, Institute of Chemical Process, Seoul National University, 3Faculty of science, Department of Physic, Materials science and nanotechnology program, Khon Kaen University The most obstacle for the performance of an anode-free battery is irregular Li plated on the hostless Cu current collector. This non-uniform Li plated causes a capacity loss and Li dendrite growth, leading to short cycle life and short circuit of the battery. The SEI layer is one of the most critical factors that affect the electrochemical cycling performance of anode free battery. The nanostructure of SEI layer could determine the shape of Li plated and uniformity of Li stripping. Inhomogeneously SEI provides the non-uniform ionic conductivity of the layer that causes the Li dendrite morphology deposition. Herein we are first to establish the optimized nanostructure of SEI by control the working potential in Li stripping. In simple control, the Li dissolution voltage cut off to 2V enable polishing the organic outer layer of SEI and maintain only homogenously inorganic inner layer. Moreover, we elucidate the organic outer layer of SEI, which easily dissolve in an electrolyte, and cracking in each cycle can cause the non-uniform Li deposition. By cryogenic electron microscopy (Cryo-TEM) features, we are revealed the nanostructure and their mechanism of 2V Li stripping enable dramatic cycle performance for anode free battery. This high potential cut off could provide over 400 cycles in Li/Cu cell at 1 mA/cm2, which is 4 time longer than normal Li/Cu cell condition. Keywords : Li-metal, anode free, dendrite, SEI Corresponding Author : Kisuk Kang (matlgen1@snu.ac.kr)	CV

02 II. Materials and Devices for Displays and Optoelectronics

Keynote Speakers

Fengjia Fan

USTC

Application of electrically excited transient absorption spectroscopy in QLED mechanism studies

Abstract

Application of electrically excited transient absorption spectroscopy in QLED mechanism studies

Fengjia Fan*1

1University of Science and Technology of China

The core working principle of LED is the radiative recombination of electron holes driven by electric field, so finding out the behavior of electron holes in LED and the distribution of electric field is crucial for analyzing and understanding the working and failure mechanism of LED, which is essential for promoting the next generation of advanced display devices, such as quantum dot LED, OLED, and OLED. The development of micro-LED is of great significance.
However, the existing instruments and equipment can not achieve this purpose. The reporter began to develop an electrically excited transient absorption spectrometer in 2017, while improving relevant theories for in-situ detection of LED carrier time, space and energy information under operating conditions, and analysis of electric field distribution. In this talk, I will selectively talk about some of key findings enabled by this instrument, such as the low efficiency cause of green InP QLED, and the origin of efficiency roll-off.

Keywords : QLED mechanisms

Corresponding Author : Fengjia Fan (ffj@ustc.edu.cn)

Zeger Hens

Ghent University

TBD

Invited Speakers

Name	Affiliation	Title	Abstract	CV
Nuri Oh	Hanyang University	Structuring and Assembling Pnictide Quantum Dots for Optoelectronic Applications	Abstract Structuring and Assembling Pnictide Quantum Dots for Optoelectronic Applications Nuri Oh*1 1Hanyang University Colloidal pnictide quantum dots (QDs), including phosphides, arsenides, and antimonides, are promising materials for next-generation optoelectronics due to their tunable electronic structures and high charge mobility. However, their synthesis remains challenging because pnictogen precursors are highly volatile and reactive, making it difficult to control size and stoichiometry. Surface oxidation further complicates their integration into devices by creating deep trap states that degrade charge transport and luminescence efficiency. To overcome these challenges, we developed a solution-phase synthesis method that uses reduced pnictogen chloride precursors with metal halides (Zn, In). This approach allows precise control over QD size and composition. In addition, a hybrid ligand-exchange strategy improves surface composition, reduces nonradiative losses, and enhances charge transport. The resulting QDs exhibit superior electronic properties, demonstrating their potential for optoelectronic device applications. To improve solvent resistance during multi-step device fabrication, we introduce thiol-mediated ligand crosslinking strategies in QD assembly. UV exposure activates thiol molecules, triggering ligand crosslinking that stabilizes QD films against solvent degradation. This process enables high-resolution micropatterning without photoresists and supports the fabrication of stretchable and reconfigurable QD structures. The reversible crosslinking process enhances form factor adaptability, ensuring compatibility with flexible and wearable electronics. This scalable and sustainable approach advances the integration of pnictide QDs in high-resolution displays, photodetectors, and emerging optoelectronic platforms. Keywords : Quantum Dot, Pnictide, Patterning, Photodetector, Display Corresponding Author : Nuri Oh (irunho@hanyang.ac.kr)	CV
Ho Jin	UNIST	Colloidal single-layer transition metal-dichalcogenide quantum dots as an emerging quantum emitter	Abstract Colloidal single-layer transition metal-dichalcogenide quantum dots as an emerging quantum emitter Ho Jin*1 1Ulsan National Institute of Science and Technology Controlled lateral quantum confinement in single-layer transition-metal chalcogenides (TMCs) can potentially combine the unique properties of two-dimensional (2D) exciton with the size-tunability of exciton energy, creating the single-layer quantum dots (QDs) of 2D TMC materials. It has the potential to act as a single-photon generator due to their relatively fast recombination times (sub-ns at cryogenic temperatures) and their unique valley properties, which offer an additional degree of freedom for quantum information applications via spin state control. Despite their potential, creating single photons from their bulk counterpart, 2D nanosheets, often requires specific conditions, such as surface defects or strains introduced by the substrate. In contrast, laterally confined 2D QDs can provide a naturally confined volume for excitons, enabling single photon generation under controlled excitation. Still, these have yet to be extensively studied as quantum light sources. Exploring such opportunities has been challenging due to the limited ability to produce well-defined 2D QDs with sufficiently high quality and size control, in conjunction with the commonly observed inconsistency in the optical properties. We report an effective method to synthesize high-quality and size-controlled 2D QDs via multilayer quantum dots (MQDs) precursors, which enables grasping a clear picture of the role of lateral confinement on the optical properties of the 2D exciton [1] and exhibiting well-defined photoluminescence (PL) spectrum free from ensemble heterogeneity [2]. Using these newly synthesized 2D QDs, we observed the strong influence of the aromatic solvents on the PL energy and intensity of 2D QD beyond the simple dielectric screening effect, which is considered to result from the direct electronic interaction between the valence band of the QDs and molecular orbital of the solvent. References 1. Jin, H. et al. High-Efficiency Photoemission from Magnetically-Doped Quantum Dots Driven by Multi-Step Spin-Exchange Auger Ionization, J. Am Chem. Soc. 2016, 138, 13253-13259. 2. Jin, H. et al. Spin-Exchange Carrier Multiplication in Manganese- Doped Colloidal Quantum Dots, Nano Lett. 2017, 17, 7471–7477. Keywords : Quantum dots, quantum emitter, transition metal-dichalcogenide Corresponding Author : Ho Jin (hojin@unist.ac.kr)	CV
Ahn Namyoung	Yonsei University	Mechanisms of colloidal quantum dot laser devices and future direction	Abstract Mechanisms of colloidal quantum dot laser devices and future direction Namyoung Ahn*1 1Yonsei University Solution-processable optical gain materials such as organic semiconductors, perovskites, and colloidal nanocrystals have attracted worldwide attention for emerging laser technologies. The realization of electrically pumped laser diodes employing this class of materials have been not demonstrated yet due to multiple remaining challenges including material stability, not sufficient optical gain, and photonic integration. Out of these solution-processable materials, colloidal nanocrystals show superior optoelectronic properties for lasing devices. These include tunable emission wavelength, low optical gain threshold, strong optical gain and high stability under ultrahigh current density operation. Toward realization of colloidal quantum dot lasers, it is of importance to precisely understand the underlying mechanism of colloidal quantum dot lasing. In this presentation, the detailed mechanism of light amplification in device with consideration of optical losses will be discussed based on numerical simulation and simple biexciton gain mechanism. Additionally, future direction for making practical laser devices employing colloidal quantum dot will be introduced. Keywords : colloidal quantum dot, laser Corresponding Author : Namyoung Ahn (n.ahn@yonsei.ac.kr)	CV
Seok Joo Yang	Gyeongsang National University	Applications of Two-Dimensional Perovskites for Perovskite Light-Emitting Diodes	Abstract Applications of Two-Dimensional Perovskites for Perovskite Light-Emitting Diodes Seok Joo Yang*1 1Gyeongsang National University Two-dimensional (2D) perovskites have garnered significant interest for their superior moisture resistance and tunable optoelectronic properties, making them promising materials for perovskite light-emitting diodes (PeLEDs). Their quantum confinement effects enable efficient emission, while the suppressed ion migration can mitigate halide segregation, a key factor affecting the long-term stability of perovskite materials. However, their lower charge transport remains a challenge for achieving high-performance optoelectronic devices. To address these issues, quasi-2D perovskites and 2D/3D heterojunctions have been explored as effective strategies to balance stability and charge transport while optimizing emission characteristics. In this presentation, I will first introduce quasi-2D perovskites as an intermediate phase between 2D and 3D structures, highlighting how controlled phase distribution can optimize energy band alignment and improve emission properties. By carefully tuning the phase composition, quasi-2D perovskites can achieve high photoluminescence quantum yield and balanced charge transport, offering a promising path toward efficient PeLEDs. I will then discuss the role of 2D/3D heterojunctions in enhancing charge injection and transport while leveraging the stability of 2D perovskites. These combined approaches demonstrate how structural and compositional control can overcome the limitations of conventional perovskites, leading to more stable and efficient PeLEDs. Additionally, I will introduce organic semiconductor-incorporated perovskites (OSiP) as a novel strategy to further enhance the optoelectronic properties of perovskite materials. The incorporation of organic semiconductors into perovskite structures enables improved charge transport, exciton management, and emission tunability, addressing key limitations of conventional perovskite systems. By integrating OSiP materials with quasi-2D and 2D/3D heterojunction strategies, we aim to develop next-generation PeLEDs with superior efficiency and stability, paving the way for their broader application in optoelectronic technologies. Keywords : Halide perovskite, 2D perovskite, Phase separation, Perovskite llight-emitting diode Corresponding Author : Seok Joo Yang (sjyang@gnu.ac.kr)	CV
Kwangdong Roh	Ehwa Womans University	Towards Electrically Driven Lasing Devices from Halide Perovskites	Abstract Towards Electrically Driven Lasing Devices from Halide Perovskites Kwangdong Roh*1 1Ewha Womans University Halide perovskites have emerged as promising materials for future optoelectronic devices, owing to their notably high photoluminescence quantum yields, tunable bandgaps, and easy/low-cost fabrication methods. Remarkably, recent studies have reported external quantum efficiencies (EQEs) above 25% in perovskite-based light-emitting diodes (LEDs) in various visible colors. Beyond these high-efficiency LEDs, there is growing momentum to develop coherent light sources from halide perovskites, where achieving both robust optical gain and a low lasing threshold is especially important for devices driven by electrical injection. Recent findings show that adjusting the dimensionality of perovskites—for example, employing two-dimensional or quasi-two-dimensional configurations—can simultaneously enhance optical gain and boost stability against environmental factors. Reduced-dimensional systems not only support population inversion at lower excitation levels but also exhibit improved resistance to moisture and oxygen. Moreover, selecting suitable spacer cations encourages the formation of either Ruddlesden–Popper (RP) or Dion–Jacobson (DJ) phases, each presenting unique optical properties. Combining these phases offers further opportunities to optimize emission and overall device performance. In this talk, we will review recent progress in halide perovskite materials and devices developed to minimize lasing thresholds and increase reliability during operation. We will highlight the design principles behind low-dimensional perovskite structures, including methods to stabilize phase formation and minimize non-radiative losses. Approaches for incorporating resonant cavities and diode layouts for effective current injection will also be explored. Lastly, we will address persistent hurdles—such as device longevity, vulnerability to environmental conditions, and scalability—while underscoring promising directions for electrically driven perovskite lasers in integrated photonics, display technologies, and optical communications. Keywords : Halide Perovskites, Lasers, Light-Emitting Diodes, Feedback Corresponding Author : Kwangdong Roh (kroh@ewha.ac.kr)	CV
Jeongkyun Roh	Pusan National University	Colloidal Quantum Dot Light Emitting Diodes Beyond Display Applications	Abstract Colloidal Quantum Dot Light Emitting Diodes Beyond Display Applications Jeongkyun Roh*1 1Pusan National University Colloidal quantum dots (QDs) have attracted significant attention as next-generation emitters due to their size-tunable emission wavelengths, near-unity photoluminescence quantum yield, narrow emission linewidth, and compatibility with large-area solution processing. These attributes, combined with the ongoing drive toward self-emissive displays, have enabled quantum dot light-emitting diodes (QD-LEDs) to surpass theoretical limits of external quantum efficiency and achieve operational lifetimes suitable for commercialization. Building on this success, QD-LEDs are now extending their impact beyond displays, including lighting and optical communications. In this talk, I will present recent progress in advancing the capabilities of QD-LEDs for both lighting and optical communication applications. For lighting, I will highlight strategies to achieve high-luminescence, large-area QD-LEDs with excellent uniformity, and discuss their use in automotive taillights, where device stability is critical. In the area of optical communications, I will cover approaches to obtain highly directional emissions and high-frequency operation, emphasizing the advantages of QD-LEDs. This presentation will explore the substantial opportunities and ongoing challenges faced by QD-LEDs as they broaden their range of applications. Keywords : Quantum dots, quantum dot light-emitting diodes, lighting, optical communication Corresponding Author : Jeongkyun Roh (jkroh@pusan.ac.kr)	CV
Huaibin Shen	Henan University	TBD
Sanghyo Lee	Kumoh National Institute of Technology	Textile electronics with multifunctional fiber devices for smart home applications	Abstract Textile electronics with multifunctional fiber devices for smart home applications Sanghyo Lee*1 1Kumoh National Institute of Technology An integrated textile electronic system is reported here, enabling a truly free form factor system via textile manufacturing integration of fiber-based electronic components. Intelligent and smart systems require freedom of form factor, unrestricted design, and unlimited scale. Initial attempts to develop conductive fibers and textile electronics failed to achieve reliable integration and performance required for industrial-scale manufacturing of technical textiles by standard weaving technologies. Here, we present a textile electronic system with functional one-dimensional devices, including fiber photodetectors (as an input device), fiber supercapacitors (as an energy storage device), fiber field-effect transistors (as an electronic driving device), and fiber quantum dot light-emitting diodes (as an output device). As a proof of concept applicable to smart homes, a textile electronic system composed of multiple functional fiber components is demonstrated, enabling luminance modulation and letter indication depending on sunlight intensity. Keywords : Textile electronics, Fiber devices, Smart home, Quantum Dots Corresponding Author : Sanghyo Lee (sanghyo.lee@kumoh.ac.kr)	CV
Hwan-Hee Cho	Yonsei University	Towards next-generation blue OLEDs based on hyperfluorescence	Abstract Towards next-generation blue OLEDs based on hyperfluorescence Hwan-Hee Cho*1 1Yonsei University Hyperfluorescence, a cutting-edge emission concept, has emerged as a promising contemporary solution for next-generation organic light-emitting diodes (OLEDs). It offers the potential to simultaneously achieve high efficiency, stability, brightness, and color purity in OLED displays. In general, hyperfluorescence is a three-component system consisting of a host matrix, thermally activated delayed fluorescence (TADF) donor, and fluorescent acceptor. Fundamentally, the primary role of the host matrix is to suppress concentration quenching and aggregation of the TADF donors as well as Dexter transfer of triplets from the donor to the acceptor – two phenomena that can lead to substantial reductions in EQE. However, it should be taken into account that a wide-gap host matrix can reduce power efficiency, resulting from a considerable increase in driving voltage. A three-component EML also increases the complexity and cost of device fabrication. In my recent study, near 100% internal quantum efficiency was demonstrated from a two-component matrix-free hyperfluorescence with deep and pure blue emission for the first time by combining efficient nondoped TADF materials and ultranarrow deep blue emitters. This was achieved by covalent encapsulation of ultranarrow emissive pure blue emitters to suppress Dexter transfer of triplets, supported by detailed photophysical studies. Furthermore, we develop and modify efficient non-doped blue TADF materials to promote Förster resonance energy transfer. Thus, further increased external quantum efficiency of >22%, CIE ~0.15, and full-width at half-maximum <14-15 nm at a peak wavelength of 456 nm were achieved based on matrix-free hyperfluorescence. This result is a significant step towards substantially improved blue OLED performance, potentially resolving or minimizing burn-in in OLED displays. Keywords : Hyperfluorescence, TADF, OLED, energy transfer Corresponding Author : Hwan-Hee Cho (chohh@yonsei.ac.kr)	CV

03 III. Materials and Devices for Smart Sensors

Keynote Speakers

Wen Jung Li

City University of Hong Kong

TBD

CV

Invited Speakers

Name	Affiliation	Title	Abstract	CV
Yu-Lun Chueh	National Tsinghua University	Innovative Phase/Structure-Engineered Two-Dimensional Layered Hybrid Films for Smart Sensors	Abstract Innovative Phase/Structure-Engineered Two-Dimensional Layered Hybrid Films for Smart Sensors Yu-Lun Chueh*1 1National Tsing Hua University Novel condensed matter systems can be understood as new compositions of elements or old materials in new forms. According to the definition, various new condensed matter systems have been developed or are under development in recent years. 2D layered materials, including graphene and transition metal dichalcogenides (TMDs) allow the scaling down to atomically thin thicknesses and possess unique physical properties under dimensionality confinement. The chemical vapor deposition (CVD) process is the most popular approach for all kinds of 2D materials due to its high yield and quality. Nevertheless, the need for high temperature and the relatively long process time within each cycle hinders commercial development in terms of production cost. However, the transfer procedure has become one of the major limitations of the overall performance. In my talk, an inductively coupled plasma (ICP) was used to synthesize Transition Metal Dichalcogenides (TMDs) through a plasma-assisted selenization process of metal oxide (MOx) at a low temperature. Compared to other CVD processes, ICP facilitates the decomposition of the precursors at lower temperatures. We create the phase/structure-engineered-1T/2H 3D-hierarchical 2D materials derived from the MOx 3D-hierarchical nanostructures through a low-temperature plasma-assisted selenization process with controlled shapes grown by a glancing angle deposition system (GLAD). The applications on gas sensors and photo detectors will be reported. Keywords : Two-Dimensional Layered Hybrid Films; plasma-assisted selenization process; phase/structure-engineered-1T/2H 2D materials, Gas sensors Corresponding Author : Yu-Lun Chueh (ylchueh@mx.nthu.edu.tw)	CV
Hyunhyub Ko	UNIST	Biomimetic Soft Sensors	Abstract Biomimetic Soft Sensors Hyunhyub Ko*1 1Ulsan National Institute of Science and Technology Skin-like soft sensors with high sensitivities have gained great attention in the fields of human-machine interfaces, robotic skins, and healthcare applications. Although various types of wearable soft sensors based on novel materials and sensing mechanisms have been introduced, there remain challenges in their practical applications. To address these challenges, we draw inspiration from biological systems, which have evolved unique micro/nanostructures with excellent sensory capabilities and functions through continued adaptation to environmental changes. Inspired by the structure and function of biological systems, we present several structural design strategies for micro/nanostructured polymer composites as soft sensors with excellent sensing capabilities and their applications in wearable devices and human-machine interfaces. First, inspired by the fingertip skin structure and function, we develop multifunctional electronic skins capable of differentiating various mechanical stimuli (normal, shear, stretching, bending), static and dynamic pressure, and temperature with high sensitivities. Second, inspired by the sound frequency tunability of the cochlea, we demonstrate frequency-selective acoustic and haptic sensors for dual-mode human–machine interfaces (HMIs) based on triboelectric sensors with hierarchical ferroelectric composites. Finally, mimicking stimuli-responsive color changing structures found in biological systems, we present colorimetric tactile sensors that can monitor external forces based on the color change signals. Keywords : electronic skin, biomimetic, soft sensor, touch sensor, acoustic sensor Corresponding Author : Hyunhyub Ko (hyunhko@unist.ac.kr)	CV
Junseong Ahn	Korea University	All-inorganic nanoribbon yarns for wearable transducers	Abstract All-inorganic nanoribbon yarns for wearable transducers Junseong Ahn*1 1Korea University, Sejong Campus The advancement of all-inorganic nanoribbon yarns is revolutionizing wearable transducer technologies by integrating energy storage, sensing, and thermoelectric energy harvesting into a single, flexible platform. These yarns, fabricated using nanoimprinting and physical vapor deposition, exhibit exceptional mechanical resilience, high surface-area-to-volume ratios, and tunable electrical and thermoelectric properties. Transition metal oxide (TMO)-based nanoribbon yarns have been successfully implemented in fiber supercapacitors, offering high energy/power densities and long-term stability, making them ideal for energy storage in wearable electronics.[1] Additionally, these yarns demonstrate high sensitivity in gas and pressure sensors, broadening their application in environmental monitoring and biomedical devices.[2] Furthermore, all-inorganic thermoelectric yarns composed of Bi₂Te₃ nanoribbons enable efficient waste heat harvesting, providing a new avenue for self-powered wearable systems.[3] These thermoelectric yarns maintain excellent mechanical flexibility, withstanding extreme bending and stretching conditions while maintaining electrical stability. By integrating energy harvesting, storage, and transduction functionalities, all-inorganic nanoribbon yarns offer a scalable and versatile solution for next-generation self-powered smart textiles and bio-integrated electronics. Their unique material properties and structural adaptability pave the way for high-performance, autonomous wearable systems in health monitoring, soft robotics, and sustainable energy applications. Keywords : Nanoribbon yarn, inorganic materials, nanoimprinting lithography, smart textile Corresponding Author : Junseong Ahn (junseong@korea.ac.kr)	CV
Isao Shitanda	Tokyo University of Science	Printable wearable biosensing devices for Health Monitoring	Abstract Printable wearable biosensing devices for Health Monitoring Isao Shitanda Tokyo University of Science Key words; wearable device, biosensor, biofuel cell, on-body test Recently, wearable biosensors that detect physiological indicators in body fluids such as sweat, saliva, and tears have been developed for the early detection and prevention of diseases. These devices can be worn during daily life or exercise to diagnose exercise efficiency and health conditions, and are useful for health monitoring. They are also attracting attention in the fields of medicine and welfare. We have been researching biosensors and self-powered biosensors using porous carbon materials with controlled nano/meso/macropores 1). In particular, we have investigated a biosensing system that can improve output and wirelessly transmit data using carbon materials with a pore structure controlled using magnesium oxide (MgO) as a template (hereafter, MgOC). We have applied this system to continuous monitoring of lactate in sweat and sugar in urine. These can be expected to be next-generation healthcare devices. 1) I. Shitanda and S. Tsujimura, J. Physics-Energy, 3, 10 (2021).	CV
Pengcheng Xu	Chinese Academy of Sciences (SIMIT)	Operando characterization of sensing mechanisms based on gas-solid interactions	Abstract Operando characterization of sensing mechanisms based on gas-solid interactions Pengcheng Xu*1 1Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences The gas-solid interface is the fundamental basis for the effects observed in gas sensing. By exploring its structural characteristics and surface activity, we can gain a deeper understanding of its reaction mechanisms and kinetic processes. Traditional studies of interface properties primarily rely on ex-situ characterization methods, which often hinder the capability to monitor the evolution of materials in real time under working conditions. With advancements in in-situ characterization techniques, such as gas-cell in-situ transmission electron microscopy (TEM), there is now an opportunity for continuous observation of samples. However, achieving ultra-sensitive quantitative measurements and conducting multi-instrument synchronous analysis remain significant challenges. In recent years, we have developed a series of operando characterization methods based on micro-electromechanical systems (MEMS) chips to address these issues. For instance, we utilized in-situ TEM and resonant cantilevers for joint characterization to reveal the mass change and activation energy of a single Ag nanowire during corrosion in a NO2-containing atmosphere, while also observing structural evolution in combination with in-situ Raman spectroscopy. Additionally, we have explored in-situ temperature-programmed desorption (TPD) based on the highly sensitive mass detection characteristics of the resonant cantilever. For example, we employed cantilever-TPD technology to quantitatively measure the active adsorbed oxygen species on nanogram-level SnO2 nanobelts and determined the desorption activation energy of various oxygen species. Notably, the relationship between the adsorbed oxygen and gas-sensitive properties was established without relying on indirect factors such as oxygen vacancies. In summary, we have developed a series of operando characterization methods using MEMS chips, including resonant microcantilevers. Our work provides innovative ideas and technical support for understanding the kinetics of gas-solid reactions and facilitating the optimization of functional nanomaterials. Keywords : MEMS chips, Operando characterization, Gas sensors Corresponding Author : Pengcheng Xu (xpc@mail.sim.ac.cn)	CV
Hongyun So	Hanyang University	Smart Sensors, Actuators, and Functional Surfaces Using FDM 3D Printing Technology	Abstract Smart Sensors, Actuators, and Functional Surfaces Using FDM 3D Printing Technology Hongyun So*1 1Hanyang University Sensors and actuators, which serve a variety of functions, are crucial in fields like mechanical, electrical, biomedical, chemical, and industrial engineering. These devices are typically small, often only a few millimeters in size, and many recent studies focus on enhancing their sensitivity or the movement of actuators by incorporating different 3D structures. While the top-down approach using microfabrication techniques is commonly used to produce these devices, it has limitations such as the need for multiple steps, post-processing, and reliance on expensive equipment and cleanroom environments. FDM (fused deposition modeling) 3D printing, a popular method in additive manufacturing, offers benefits such as low material costs and fast printing speeds. However, one of its drawbacks is the rough surface finish of printed objects. In recent research, it has been found that 3D printing can enable the creation of intricate patterns that would be difficult to achieve with traditional semiconductor processes. This presentation explores various 3D printing techniques as alternatives to conventional microfabrication methods and provides performance evaluations and reliability test results for sensors and actuators produced with these methods. Keywords : FDM printing, Staircase effect, Sensors, Actuators, Functional surfaces Corresponding Author : Hongyun So (hyso@hanyang.ac.kr)	CV
Zhuo Li	Fudan University	Flexible pressure/strain sensors and quantum tunneling effect	Abstract Flexible pressure/strain sensors and quantum tunneling effect Zhuo Li*1, Shuxing Mei1, Haokun Yi1, Limin Wu1, Lan Shi1, Guoqing Yang1 1Fudan University Flexible pressure and strain sensors have attracted wide attention due to their applications in health monitoring, VR/AR devices, sporting equipment, and robotics. Achieving high sensitivity in resistive sensors typically involves two strategies: percolation theory and alterations in contact resistance. However, the quantum tunneling effect of nanomaterials offers a less explored yet promising avenue for enhancing sensitivity. In this talk, I will introduce four recent studies conducted by our team on quantum tunneling. In our initial study, we utilized vertically aligned carbon nanotubes (VACNTs) as field emitters and a spin-coated polymethyl siloxane (PDMS) layer as both insulator and pressure sensing material. The thinning of the PDMS layer under pressure reduced the tunneling barrier for electrons from VACNTs, resulting in a significant increase in tunneling current. This sensor not only set sensitivity records but also achieved ultrahigh precision. In a subsequent study, we employed spiky hollow carbon nanospheres dispersed in a PDMS matrix, leading to a sensor array with ultrahigh sensitivity and a high sensing density that is six times higher than the human finger. Further research involved organizing these nanospheres into compact films through floating assembly, followed by the creation of dense sensing array using laser ablation. This stretchable strain sensing array exhibit a high gauge factor of 70000 and a sensing density of 100/cm2. Additionally, we will discuss methods to mitigate quantum tunneling in capacitive pressure sensors to improve signal-to-noise ratios. Keywords : Pressure sensor; Strain sensor; Quantum Tunneling Corresponding Author : Zhuo Li (zhuo_li@fudan.edu.cn)	CV
Miso Kim	KAIST	Tailoring Piezoelectric Polymer Fibers for Self-Powered Sensing Applications	Abstract Tailoring Piezoelectric Polymer Fibers for Self-Powered Sensing Applications Miso Kim*1 1Korea Advanced Institute of Science and Technology Piezoelectric polymer fibers offer a versatile platform for self-powered sensing and energy harvesting across various applications. This presentation will highlight our research team’s recent advancements in customizing the properties of these fibers, emphasizing materials and structural strategies aimed at enhancing self-powered sensing capabilities, often integrated with artificial intelligence. Key innovations include solvent-controlled techniques for enhanced electroactive phase formation, as well as surface porosity engineering to increase voltage output in electrospun fibers. We explore the incorporation of inorganic nanoparticles to improve both the piezoelectricity and mechanical strength of yarn structures derived from these fibers, alongside the development of tailored convolutional neural networks for accurate, real-time classification of human motion. Laminate-inspired stacking techniques will also be discussed to optimize yarn structures. While previous studies have demonstrated the utility of these materials in creating flat or yarn-shaped devices for self-powered sensing, challenges with stretchability, durability, and reliance on metal electrodes have limited broader applications. To address these issues, we fabricated piezoelectric helical coils (PHCs) using a twisting process and integrated organic electrodes, conducting a thorough parametric study to analyze mechanical and piezoelectric properties, which led us to identify optimal conditions for high-performance PHCs. Furthermore, stretchability and resilience were enhanced by mechanically interlocking PHCs with elastic polymers through electrospraying. By integrating conductive polymer electrodes instead of traditional metal electrodes, we maintained flexibility while effectively extracting piezoelectric signals. This presentation will underscore the significance of these advancements in enhancing the performance of self-powered sensors for motion detection, environmental monitoring, and biomedical applications. Keywords : piezoelectric; fiber; electrospinning; self-powered sensing, energy harvest Corresponding Author : Miso Kim (misokim@kaist.ac.kr)	CV
Sungjun Park	Ajou University	Ultra-flexbile organic optoelectronic devices	Abstract Ultra-flexbile organic optoelectronic devices Sungjun Park*1 1Ajou University Ultra-flexible organic optoelectronic devices are transforming the future of biomedical and wearable technologies in the Internet of Things era. The unique flexibility of organic materials, combined with their low-cost and scalable processing methods, has accelerated the development of these advanced devices. However, to fully unlock the potential of next-generation wearables and sensors, it is essential to enhance both their electronic performance and mechanical durability. In this presentation, I will review recent breakthroughs and discuss the challenges that remain in the field of ultra-flexible organic electronics. Our focus is on preliminary results achieved through strategic material selection and structural engineering, which have led to the development of energy harvesters and sensors designed to interface seamlessly with human skin. A key objective is ensuring that these devices maintain optimal photonic and electrical performance even when subjected to mechanical stress. By sharing our findings, we aim to inspire further research in areas such as wearable technology, primary healthcare, medical applications, and motion recognition for AR/VR. Continued innovation in ultra-flexible electronics holds the promise of integrating advanced devices into our daily lives, ultimately enhancing human well-being and expanding the horizons of technological possibilities. Keywords : Organic electronics, Wearable devices, Ultra-thin devices, Optoelectronics Corresponding Author : Sungjun Park (sj0223park@ajou.ac.kr)	CV
Morteza Amjadi	University of Glasgow	TBD

04 IV. Materials, Processing, and Devices for Unconventional Electronics

Keynote Speakers

Tsuyoshi Sekitani

Osaka University

Advancing Brain-Machine Interfaces: Functional Materials and Soft Electronics for High-Performance Neural Interfaces

Abstract

Advancing Brain-Machine Interfaces: Functional Materials and Soft Electronics for High-Performance Neural Interfaces

Tsuyoshi Sekitani*

The Institute of Scientific and Industrial Research, Osaka University
*E-mail: sekitani@sanken.osaka-u.ac.jp

In this presentation, I will introduce the research and development of Brain-Machine Interfaces (BMIs) using flexible and stretchable electronics, characterized by their softness, as well as efforts toward their social implementation [1-7]. Specifically, I will discuss the current development status, application examples, challenges, and future prospects of BMI technology, which consists of four types: invasive, minimally invasive, non-invasive, and non-contact systems.

BMI technology has already reached a practical level, with particularly high expectations in the medical field. Clinical development, including clinical trials and medical device certification, is underway. A key challenge in BMI design lies in balancing two crucial performance factors: degree of invasiveness and measurement accuracy (temporal and spatial resolution), which generally have a trade-off. Non-invasive BMIs are easy to use but tend to have lower measurement accuracy, while high-accuracy BMIs often require invasive procedures, limiting their practical applications. To address this issue, it is essential to develop a diverse range of BMI systems tailored to different needs. Moreover, integrating data from various BMI types enables the creation of a comprehensive Brain-Big-Data framework.

To advance BMI technology, we focus on the development and application of functional materials and biocompatible materials that exhibit high flexibility, stretchability, and superior electrical properties. These materials serve as the foundation for next-generation electronic devices that enhance BMI performance by reducing mechanical mismatches with biological tissues, improving signal fidelity, and enabling long-term stability. In this research, we leverage these materials along with nanomaterials and nanofabrication technologies to minimize invasiveness while enhancing signal quality.

Building on this core technology, we are advancing the development and social implementation of intracranial, intravascular, wearable, and non-contact BMIs. In this presentation, I will showcase examples of their application in collaboration with medical institutions, highlighting how these advanced materials and electronic devices contribute to the future of BMI technology.
Part of this research was supported by JST Moonshot Goal 1 (JPMJMS2012).

References
[1] T. Araki, T. Sekitani, et. al., “Broadband Photodetectors and Imagers in Stretchable Electronics Packaging”, Advanced Materials 2304048 (2023).
[2] A. Petritz, T. Sekitani, et. al., “Imperceptible energy harvesting device and biomedical sensor based on ultraflexible ferroelectric transducers and organic diodes”, Nature Communications 12, 2399 (2021).
[4] K. Taguchi, T. Sekitani et. al., “Heterogeneous Functional Dielectric Patterns for Charge-Carrier Modulation in Ultraflexible Organic Integrated Circuits”
Advanced Materials 33, 2104446 (2020).
[5] M. Sugiyama, T. Sekitani, et. al., “An ultraflexible organic differential amplifier for recording electrocardiograms”, Nature Electronics 2, p. 351 (2019).
[6] Tsuyoshi Sekitani, “The disappearing boundary between organism and machine”, Science 380, 690 (2023). Perspective
[7] Tsuyoshi Sekitani, “A photocurable bioelectronics–tissue interface”, Nature Materials 20, 1460 (2021). News&Views

CV

Woon-Hong Yeo

Georgia Institute of Technology

Smart and Connected Sensors and Bioelectronics for Human-Machine Interfaces and Advanced Healthcare

Abstract

Smart and Connected Sensors and Bioelectronics for Human-Machine Interfaces and Advanced Healthcare

W. Hong Yeo*1

1Georgia Tech

In this talk, Dr. Yeo will share the basic scientific study of integrated soft sensors and electronics in both wearable and implantable configurations. He will talk about the limitations of the existing biomedical systems used in continuous health monitoring, persistent human-machine interfaces, and disease diagnosis. A set of new solutions that can tackle these issues will be shared with the details. Specifically, he will discuss unique strategies for designing and fabricating new systems using soft and hybrid materials. In terms of recent outcomes, he will introduce a few projects that develop soft electronic sensors and platforms targeting persistent human-machine interfaces (human augmentation via wearable exoskeletons), sleep quality and disorder quantification and detection, and wearable auscultation for continuous heart and lung sound detection. In vitro and in vivo study examples will capture the novelty of these soft electronic systems and their major advantages over the existing systems in real-time continuous health monitoring, portable healthcare, quantitative disease diagnosis, and connected therapeutics with human-machine interfaces.

CV

Invited Speakers

05 V. Two-dimensional Materials and van der Waals Heterostructures

Keynote Speakers

Barbaros Özyilmaz

NUS

Multilayer Amorphous Carbon for Advance Microelectronics

Abstract

Multilayer Amorphous Carbon for Advance Microelectronics

Barbaros Oezyilmaz*1

1Materials Science and Engineering Department, Physics Department, Centre for Advanced Materials (CA2DM), Institute for Functional Intelligent Materials (I-FIM), National University of Singapore

Unlike defectiv materials or nanocrystaline materials, amorphous materials are heavily disordered yet structuraly stable. This allows the observation of unusual electronic states and reshapes their energy-momentum dispersion [1-3]. Furthermore, their heavily disordered atomic potential can drastically alter the local density of states (LDOS). In this context, I will discuss Multilayer Amorphous Carbon (ML-AC). Its freestanding, corrogated 2D nature corregated corrugation challenge the conventional Bloch-state framework, enabling new perspectives on 2D Anderson insulator physics and multifractal electronic states. Its fundamental properties help address a number of current challenges especially in the microelectronics industry. For example, ML-AC uniquely achieves a high degree of disorder without sacrificing material density and structural integrity. This overcomes typical leakage issues of Anderson insulators under bias relevant for low power electronics. Utilizing non-polar carbon-carbon bonding and suppressing electronic polarization through disorder enables access to ultra-low-k insulating properties (k~1.35). The latter has the potential to address the RC delay bottleneck in interconnect scaling, offering a viable alternative to conventional dielectrics such as SiCOOH. Its chemical stability, random atomic structure and exceptional adhesion—derived from intrinsic atomic corrugation—make it a promising candidate for copper diffusion barriers and interface layers in transistor stacks with a time to failure in excess of TTF~ 1010s. Its highly non-uniform electron density landscape allows it to also act as a seed layer. I will conclude with recent results on volatile switching in graphene–MAC–graphene heterostructures, positioning MAC as a potential selector or neuron element in neuromorphic architectures.

1. Corbae, P. et al. Observation of spin-momentum locked surface states in amorphous Bi2Se3. Nat. Mater (2023).
2. Khan, A. I. et al. Surface conduction and reduced electrical resistivity in ultrathin noncrystalline NbP semimetal. Science (2025).
3. Toh, C.-T. et al. Synthesis and properties of free-standing monolayer amorphous carbon. Nature 577, 199–203 (2020).

Keywords : MAC, ML-AC, monolayer amorphous carbon, ultralow k dielectrics, interconnects, diffusion barrier

Corresponding Author : Barbaros Oezyilmaz (phyob@nus.edu.sg)

Kian Ping Loh

PolyU

Phase engineering of 1T’-MoTe2 for Non-linear Hall effect

Abstract

Phase engineering of 1T’-MoTe2 for Non-linear Hall effect

Kian Ping Loh*1, Kian Ping Loh2

1Hong Kong Polytechnic University, 2National University of Singapore

The reduced symmetry in strong spin-orbit coupling materials such as transition metal ditellurides (TMDTs) gives rise to non-trivial topology, unique spin texture, and large charge-to-spin conversion efficiencies. Intrinsic Spin Hall effect (SHE), a hallmark of materials with substantial spin-orbit coupling (SOC), can be exploited to achieve all-electrical generation and detection of spin current, which is a key prerequisite to fulfil the potential of spintronics
The nonlinear Hall effect (NLHE), first reported experimentally by Pablo of MIT in bilayer WTe2, has garnered increasing attention recently because of its rich fundamental physics and potential application in RF rectification. Besides being a sensitive probe of topological phase transition, NLHE rectifies a.c. current to d.c, thus they can be useful as RF rectifier. We observed large in-plane nonlinear Hall (NLH) effect for the bilayer and trilayer Td phase MoTe2 under time reversal-symmetric conditions, while these vanish for thicker layers. For a fixed input current, bilayer Td MoTe2 produces the largest second harmonic output voltage among the thicker crystals tested. However, the non-linear Hall effect vanishes by room temperature. To address this, polytype engineered 3T’ phase as well as edge-pinned room temperature stable Td phase were fabricated and their non-linear Hall and Planar Hall effect studied. These polytype phases can be distinguished by their interlayer phonon modes from the conventional 1T’ phases. The breaking of inversion symmetry in this phase enables the observation of large room temperature non-linear transverse second harmonic response.

References
[1] Song, P. Kian Ping Loh* et al. Coexistence of large conventional and planar spin Hall effect with long spin diffusion length in a low-symmetry semimetal at room temperature. Nat. Mater. 19, 292–298 (2020).
[2] Ma, T., Chen, H., Yananose, K. Kian Ping Loh* et al. Growth of bilayer MoTe2 single crystals with strong non-linear Hall effect. Nat Commun 13, 5465 (2022). https://doi.org/10.1038/s41467-022-33201-3

Keywords : MoTe2; non-linear hall effect

Corresponding Author : Kian Ping Loh (kploh@polyu.edu.hk)

CV

Invited Speakers

Name	Affiliation	Title	Abstract	CV
Minsoo Kim	Sogang University	Topologically Protected One-Dimensional Quantum Transport in Twisted Graphene	Abstract Topologically Protected One-Dimensional Quantum Transport in Twisted Graphene Minsoo Kim*1 1Sogang University The pursuit of robust one-dimensional (1D) quantum transport channels offers promising opportunities for exploring novel physics with non-trivial topology and has significant implications for metrology and device technology. Marginally twisted graphene at small angles (~0.1°) presents an exceptional platform for such investigations, where chiral one-dimensional states form along domain boundaries during lattice reconstruction into submicron triangular domains with Bernal stacking. Our research demonstrates Aharonov-Bohm oscillations resulting from electron interference within this chiral network. The topological protection of these states is evidenced by their strong phase coherence, which persists at temperatures exceeding 100 K. We also observed remarkable superconducting proximity effects in the quantum Hall regime, where Josephson junctions continue to function near the upper critical field of the superconducting electrodes. Notably, the critical current exhibits non-oscillatory behavior, with magnitudes constrained by the quantum conductance of ballistic 1D channels within the domain walls. These findings suggest promising avenues for the advancement of topological superconductivity and topological quantum computation. Keywords : graphene, topology, quantum interference, superconductivity, Josephson junction Corresponding Author : Minsoo Kim (minsoo@sogang.ac.kr)	CV
Kaihui Liu	Peking University	Optical crystals of 2D materials	Abstract Optical crystals of 2D materials Kuihui Liu*1, / /2 1中国, 2/ Nonlinear optical crystals are the key components in advancing laser technology, offering the crucial functionalities of frequency conversion, signal modulation and parameter amplification. Over the last few decades, the utilization of well-established materials for nonlinear optical crystals like BBO, LiNbO3, and KBBF has contributed to the fast development of quantum light sources, photonic integrated circuits and ultrafast lasers. The pursuit of suitable nonlinear optical crystals has led to the exploration of the potential in two-dimensional (2D) materials with rhombohedral structures, due to its high nonlinear susceptibility, broadband transparency, remarkable physicochemical stability, and compatibility with Si-based optical chips. However, the preparation of large-sized single-crystal 2D layers remains an extreme challenge. In this talk, I will introduce some recent progresses in the growth of large single-crystal rBN and 3R-MoS2 layers with both in-plane and out-of-plane controls[1-4], as well as the development of the twist-phase-matching theory for the design of 2D nonlinear optical crystals[5-6]. Twisted 2D nonlinear optical crystals will be a new useful optical crystal for future photonic and optoelectronic applications. Keywords : 2D materials；nonlinear optics； optical crystals Corresponding Author : Kuihui Liu (khliu@pku.edu.cn)
Luis A. Jauregui	UC Irvine	Topological Phase Transitions for Novel Quantum Electronic Devices	Abstract Topological Phase Transitions for Novel Quantum Electronic Devices Luis A. Jauregui, University of California, Irvine Topological materials provide a promising platform for next-generation quantum electronic devices due to their symmetry-protected states and resilience to disorder. In this work, we investigate topological phase transitions in HfTe5, where external tuning parameters such as uniaxial strain, magnetic field, and heterostructure engineering are used to drive transitions between distinct topological phases. Using high-mobility van der Waals materials, we observe clear signatures of transitions—from weak to strong topological phases—through magneto-transport measurements, edge state conduction, and quantum oscillations. These findings are integrated into functional devices that exploit the reconfigurable nature of topological states, enabling control over charge and spin. Our results establish a foundation for tunable quantum electronic components that harness topological phase transitions as a functional degree of freedom.	CV
Kathy Kai LENG	PolyU	Molecularly Thin 2D Organic-Inorganic Hybrid Perovskite: Structure, Properties and Device Applications	Abstract Molecularly Thin 2D Organic-Inorganic Hybrid Perovskite: Structure, Properties and Device Applications Kai LENG*1, Chuanzhao Li1 1The Hong Kong Polytechnic University 2D Organic-Inorganic Hybrid Perovskites (OIHPs) are functional materials that exhibit unique properties. The chemical composition of OIHPs can be easily modified, encouraging researchers to design new crystals with diverse properties. The advent of atomically thin 2D materials has shifted the research focus from bulk crystals to molecularly thin OIHPs, which are truly two-dimensional. Isolating OIHP monolayers with clean, flat surfaces is essential for atomic structure characterization and device fabrication, yet this remains a significant challenge. In this talk, I will present recent advancements in molecularly thin 2D OIHPs, focusing on my work with devices such as photodetectors, FETs, and charge-to-spin converters. Unlike their bulk counterparts, monolayer OIHPs demonstrate unique physical properties, achieving an internal quantum efficiency of 34%, compared to 19% for bulk crystals. I have also addressed the challenge of determining surface atomic structure of OIHPs. We employed Scanning Tunneling Microscopy (STM) and Qplus AFM to directly visualize surface octahedral tilting in molecularly thin 2D OIHPs. The observed surface-enhanced octahedral tilt was found to correlate with their excitonic and spin properties. Upping the ante in design of new perovskites, we invented a new class of molecularly thin 2D all-organic perovskites, showing significant potential as gate dielectrics for thin-film transistors. Keywords : Molecularly Thin 2D Hybrid Perovskite Corresponding Author : Kai LENG (kathy-kai.leng@polyu.edu.hk)	CV
Hyunseob Lim	GIST	Influence of Substrate Surface Chemistry and Precursor Interactions on the Growth of 2D Transition Metal Dichalcogenide Films	Abstract Influence of Substrate Surface Chemistry and Precursor Interactions on the Growth of 2D Transition Metal Dichalcogenide Films 1Gwangju Institute of Science and Technology The high-quality synthesis of two-dimensional transition metal dichalcogenide (TMD) films critically depends on carefully controlled substrate surface chemistry and the nature of interactions between substrates and molecular precursors. Here, we systematically examine how these parameters collectively govern the growth of uniform, high-quality monolayer and multilayer TMD films, specifically focusing on MoS₂ and WS₂. Our approach involves the development and utilization of vapor pressure-controllable inorganic molecular precursors, facilitating precise modulation of precursor-substrate interactions. We demonstrate that stronger interactions significantly lower nucleation barriers, promoting uniform nucleation and resulting in homogeneous, highly crystalline monolayer WS₂ and MoS₂ films. Conversely, weaker interactions lead to irregular nucleation and less uniform film morphologies, particularly influencing multilayer growth. In addition, we reveal the pivotal role of sapphire (α-Al₂O₃) substrate surface termination in crystallographic epitaxial growth. Hydroxyl-terminated substrates enhance precursor adsorption, promoting epitaxial alignment and improved crystallinity. In contrast, substrates with oxygen-rich terminations yield increased disorder and heterogeneous nucleation due to weaker, less specific interactions. By integrating these findings, we provide comprehensive insights into how substrate chemistry and precursor interactions can be strategically manipulated to achieve precise control over TMD film characteristics. These insights form the foundation for optimizing TMD synthesis processes for advanced electronic, optoelectronic, and energy-related applications. Keywords : MoS2, epitaxial growth, surface termination Corresponding Author : Hyunseob Lim (hslim17@gist.ac.kr)	CV
Seunguk Song	Sungkyunkwan University	Metal-organic chemical vapor deposition of two-dimensional indium selenides and their phase control	Abstract Metal-organic chemical vapor deposition of two-dimensional indium selenides and their phase control Seunguk Song*1 1Sungkyunkwan University The two-dimensional (2D) indium selenides (InSe and In2Se3) have garnered attention as a highly desirable ultrathin III-VI semiconductor, possessing favorable qualities akin to III-V semiconductors and 2D van der Waals transition metal dichalcogenides. However, due to the complexity of the In-Se system and challenges related to promoting lateral growth, large-area, phase-selective synthesis of 2D InSe and In2Se3 has proved difficult. Here, our work presents a successful method for the growth of high-quality and thickness-controlled 2D InSe and In2Se3 thin films using vertical, cold-walled metal-organic chemical vapor deposition. By interrupting the Se source periodically, we create an environment deficient in Se that favors the nucleation of InSe over In2Se3. Additionally, pulsing the Se precursor promotes lateral growth of InSe at low temperatures (360-500 °C), allowing us to produce highly stoichiometric, crystalline thin films on 2-inch sapphire substrates. Importantly, these growth temperatures are compatible with back-end-of-line integration in Si microelectronics. The resulting 2D domains are oriented along the crystal structure of the substrate, and the thickness can be controlled by growth time. We also demonstrate the fabrication of few-layer InSe transistors with high on-to-off current ratios (~104-105) and field-effect mobility (~2.8 cm2V-1s-1) comparable to that of mechanically exfoliated single crystals of InSe. In the case of a few-layer In2Se3, its inherent ferroelectric nature allows us to evaluate its potential as a ferroelectric semiconductor field-effect transistor with non-volatile memory. Our work offers a promising approach for creating phase-pure 2D InSe and In2Se3 films at the wafer scale, which can be adapted for other material systems with multiple polymorphs. Keywords : Two-dimensional (2D) indium selenides (InSe, In2Se3), III-VI semiconductor, Metal-organic chemical vapor deposition (MOCVD), Phase-selective synthesis Corresponding Author : Seunguk Song (seunguk@skku.edu)	CV
Yeonhoo Kim	KRISS	Evaluation of Radiation Effects in 2D Semiconductors: Importance of Precise Irradiation Parameters	Abstract Evaluation of Radiation Effects in 2D Semiconductors: Importance of Precise Irradiation Parameters Two-dimensional (2D) semiconductor materials have recently attracted significant attention as radiation-tolerant materials due to their inherent structural stability, atomic thinness, and exceptional electronic properties. To accurately evaluate their radiation tolerance, precise irradiation parameters must be clearly specified. This study utilizes highly accurate radiation measurement standards established by the Korea Research Institute of Standards and Science (KRISS), a national metrology institute capable of providing the most precise radiation measurement values within Korea. Although radiation exposure is commonly reported in terms of absorbed dose, critical irradiation parameters such as dose, fluence, flux, and radiation source type have often been overlooked. In this research, a uniform standard radiation field was established, and standard dosimeters were employed to accurately quantify the absorbed radiation dose. The study demonstrates that variations in these radiation parameters and the type of radiation source significantly influence material responses, even under identical dose conditions. These findings emphasize the critical importance of explicitly reporting detailed irradiation parameters beyond dose alone, enabling improved accuracy and deeper insights into radiation effects on 2D semiconductor devices. Keywords: 2D materials, radiation measurement standards, sensors, transistors, photodetectors Corresponding Author: Yeonhoo Kim (yeonhoo@kriss.re.kr)	CV
Zhiyuan Zeng	City University of Hong Kong	Li+ intercalation in 2D TMDs: preparation, mechanism study and applications	Abstract Li+ intercalation in 2D TMDs: preparation, mechanism study and applications Zhiyuan Zeng1* 1Department of Materials Science and Engineering, and State Key Laboratory of Marine Pollution, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong 999077, P. R. China. Email: zhiyzeng@cityu.edu.hk Intercalation of atoms, ions, and molecules is an effective means of tuning the properties of two-dimensional materials, while in situ imaging and spectroscopy provide powerful tools for deciphering intercalation dynamics and mechanisms.1,2 Firstly, we developed a lithium ion battery intercalation & exfoliation method with detailed experimental procedures for the mass production of 11 2D transition metal dichalcogenides (TMDs) and inorganic nanosheets, such as MoS2, WS2, TiS2, TaS2, ZrS2, graphene, h-BN, NbSe2, WSe2, Sb2Se3 and Bi2Te3, among them 3 TMDs achieved mono- or double layer yield > 90%.3 The Li insertion can be monitored and finely controlled in the battery testing system, so that the galvanostatic discharge process is stopped at a proper Li content to avoid decomposition of the intercalated compounds. Secondly, we discovered that small current and high cut-off voltage (0.005 A g-1, 0.9 V) produces pure 2H WS2 bilayers. while large current and low cut-off voltage (0.02 A g-1, 0.7 V) leads to 1T’ WS2 monolayers.4 For lithium intercalation mechanism, the state-of-the-art In-Situ Liquid Phase TEM is an ideal technique for identifying the phase changes during intercalation process.5 Combining with in-situ XAS, XRD and Raman, etc, the underlying lithium intercalation mechanism in TMDs were elucidated to achieve scalable production. For water decontamination, our metallic 1T/1T′ phase 2D TMDs (MoS2, WS2, TaS2, TiS2) nanosheets exhibited exceptional Pb2+ removal capacity (up to 758 mg∙g-1) with treatment capacity of 55 L-water/g-adsorbent for feeding Pb2+ concentration of 1 mg∙L-1, which is 1-3 orders of magnitude higher than other 2D materials and commercial activated carbon, holding great potential as Point-of-use (POU) devices.6 Then, a one-step covalent functionalization of MoS2 nanosheets was used for membrane fabrication, which exhibits rejection rates of >90% and >80% for various dyes and NaCl in reverse osmosis (RO).7 After that, we found that 1Tʹ-MoS2 electrode demonstrates exceptional volumetric desalination capacity of 65.1 mgNaCl cm-3 in capacitive deionization.8 References: [1] R. Yang†, L. Mei†, Z. Lin†, et al., D. Voiry, Q. Lu, J. Li, Z. Y. Zeng, Nat. Rev. Chem., 2024, 8, 410. [2] R. Yang, et al., H. S. Shin, D. Voiry, Q. Lu, J. Li, Z. Y. Zeng, Nat. Synth., 2023, 2, 101-118. [3] R. Yang, L. Mei, et al., H. S. Shin, D. Voiry, Z.Y. Zeng, Nat. Protoc., 2022, 17, 358-377. [4] L. Mei, et al., J. Li, X. Yu, Z. Y. Zeng, Nat. Synth., 2024, DOI: 10.1038/s44160-024-00679-2. [5] R. Yang, L. Mei, Y. Fan, Q. Zhang, H. G. Liao, J. Yang, J. Li, Z. Y. Zeng, Nat. Protoc., 2023, 18, 555-578. [6] L. Mei, M. Sun, R. Yang, et al., B. Huang, L. Gu, D. Voiry, Z. Y. Zeng, Nat. Commun., 2024, 15, 7770. [7] L. Mei, et al., C. Y. Tang, D. Voiry, H. Wang, A. B. Farimani, Z. Y. Zeng, Adv. Mater., 2022, 34, 2201416. [8] T. Ying, Y. Xiong, H. Peng, et al., C. Y. Tang, J. Fan, Z. Y. Zeng, Adv. Mater., 2024, 36, 2403385.	CV
Abhishek Misra	IIT Madras	Room Temperature Dipolar Excitons in van der Waals Heterostructures	Abstract Room Temperature Dipolar Excitons in van der Waals Heterostructures Abhishek Misra*1 1Indian Institute of Technology Madras Excitons are the bosonic system and thus the careful manipulation of their number density can lead to a range of many-body complexes. Excitons with permanent out-of-plane electric dipole moment interact via dipole–dipole interactions. Such excitons, known as interlayer excitons (IX) or dipolar excitons, further enrich the excitonic phase diagram depending on the nature of the dipole-dipole interaction. These appealing dipolar interactions have been the subject matter of intense investigations since decades using GaAs/AlGaAs quantum well structures. With the advent of van der walls heterostructures, the realization of dipolar excitons, at least theoretically, has become rather easy. Experimentally, these have been confirmed via luminescent emission in the heterostructures of transition metal dichalcogenides. However, in these heterostructures, the IXs are not always observed as the emission is very sensitive to the lattice mismatch and the twist angle between the constituent materials. Moreover, their emission intensity is very feeble compared to corresponding intralayer excitons at room temperature. In this talk, I will discuss a possible way to stabilize these IXs at room temperature. Room temperature stabilization of the dipolar excitons holds significance not only to explore many-body physics at elevated temperatures but also for their applications in the field of quantum technologies. Keywords : Interlayer Excitons, Dipolar Exciton, 2D materials, PbI2, 2L WS2 Corresponding Author : Abhishek Misra (abhishek.misra@smail.iitm.ac.in)	CV
Radha Boya	University of Manchester	2D material vdW heterostructures based Angstrom-scale channels	Abstract 2D material vdW heterostructures based Angstrom-scale channels Radha Boya*1 1University of Manchester Understanding molecular transport in nano/angstrom scale channels has practical relevance in applications such as membrane desalination, blue energy, supercapacitors and batteries, as well as in understanding ionic flow through biological channels [1]. In this talk, I will discuss about angstrom (Å)-scale capillaries which are created by extracting one-atomic layer out of a crystal [2]. The Å-capillaries have helped probe several intriguing molecular-scale phenomena experimentally, including: water flow under extreme atomic-scale confinement [2] steric exclusion of ions [3], specular reflection off a surface [4], voltage gating of ion flows [5]. I will discuss ionic memory effects [6] and coupling nanofluidics to manipulate quantum defect induced emission [7]. Furthermore,we can use ultramicrotomy approach to scaling up the fabrication of such channels [8]. References: [1] Y. You, A.Ismail et al., Annual Reviews for Materials Research 52, 189, (2022) [2] B. Radha et al., Nature 538, 222 (2016); A. Bhardwaj et al., Nature Protocols (2024), 19, 240 [3] S. Goutham et al., Nature Nanotechnology (2023), 18, 596; K. Gopinadhan et al., Science 363, 145 (2019) [4] A. Keerthi et al., Nature (2018), 558, 420 [5] T. Mouterde et al., Nature 567, 87 (2019) [6] P. Robin et al., Science (2023), 379, 161. [7] N. Ronceray et al., Nature Materials (2023), 22,1236 [8] A. Bhardwaj et al., Advanced Functional Materials (2024), 2401988 Acknowledgements I acknowledge the contributions to this work from my collaborators and colleagues Sir A.K. Geim, A. Keerthi, A. Ismail, S. Goutham, Y. You, S. J Haigh, R. Sajja, A. Bhardwaj, R.K. Gogoi, G.H-Nam, K. Gopinadhan, A. Esfandiar, R. Dryfe from University of Manchester; L. Bocquet, P. Robin, T. Emmerich, T. Mouterde, A. Poggioli, A. Siria, from Micromégas team, ENS Paris; A. Radenovic, N. Ronceray from EPFL and my theory collaborators N. Aluru, F.C. Wang, M. Neek-Amal. Keywords : 2D materials, heterostructures, angstrom-scale channels, ionic memory Corresponding Author : Radha Boya (radha.boya@manchester.ac.uk)	CV
Changgu Lee	Sungkyunkwan University	Spectroscopic studies of atomically thin carbon materials	Abstract Spectroscopic studies of atomically thin carbon materials Changgu Lee*1 1Sungkyunkwan University Here, two research works will be presented on spectroscopic studies of atomically thin carbon materials, which are graphene and 2D amorphous carbon film. Firstly, single layer graphene is strained up to ~6 % by atomic force microscope tips. At the same time, a laser light is focused on the strained graphene to collect Raman signal. G and 2D peaks are significantly shifted by 282 and 684 cm-1 at around 6% of strain. This is the highest strain level, where the Raman signal was measured. The experimental results and technical challenges will be discussed on this experiment. Secondly, atomically thin amorphous carbon layers were synthesized by a CVD method, and were characterized by several spectroscopic techniques, such as Raman, XPS, and Electron energy loss spectroscopies. Especially, from Raman spectroscopy, D/G peak ratios varied with different synthesis temperatures. Contrary to our conventional thought that increasing disorder would increase D peak intensity, D peak was reduced with the increasing disorder. This was attributed to the characteristics of D peak, which needs hexagonal carbon bonds for the vibration mode. Acknowledgement: These works were supported by the basic science research program of National Research Foundation of Korea (2023R1A2C200538311). Keywords : Graphene, Amorphous material, Synthesis, Spectroscopy, Mechanical Properties Corresponding Author : Changgu Lee (peterlee@skku.edu)	CV

06 VI. Advanced Structural Materials

Keynote Speakers

Shoichi HIROSAWA

YOKOHAMA National University

Evaluation of slip behavior of mobile dislocations during in-situ tensile-testing TEM observation of Al-Mg-Si alloys

Abstract

Evaluation of slip behavior of mobile dislocations during in-situ tensile-testing TEM observation of Al-Mg-Si alloys

Shoichi Hirosawa*1, Daiki Inoue2

1Yokohama National University, 2Graduate student of Yokohama National University (Present : Sumitomo Electric Industries)

In general, slip, multi-slip and accumulation behaviors of dislocations occur on the micrometer scale, whereas cutting and Orowan mechanisms involving interactions between dislocations and precipitates are formulated on the nanometer scale. In this study, mobile dislocations within commercial-purity aluminum and an Al-Mg-Si alloy with fine ß” precipitates were dynamically observed by in-situ tensile-testing transmission electron microscopy (TEM), and correlated with their deformation and strengthening mechanisms. Homogeneous dislocation movement along the primary slip systems was observed in commercial-purity aluminum, whereas a localized slip of mobile dislocations due to the dispersed ß” precipitates was followed by the expansion of deformation region with many slip traces as a result of rotation of segmented ß” precipitates.

Keywords : Dislocation, Slip behaviour, Aluminum alloy, Deformation, Precipitates, Strengthening mechanism

Corresponding Author : Shoichi Hirosawa (hirosawa@ynu.ac.jp)

CV

Hiroshi Utsunomiya

Osaka University

In situ observation of the sheet deforming in roll bite during flat rolling process

Abstract

In situ observation of the sheet deforming in roll bite during flat rolling process

Hiroshi Utsunomiya*1

1Osaka University

For direct observation of a deforming sheet in rolling, a new experimental method, where a pair of rotating rolls travel upstream, is proposed. Displacement of a reference point in the sheet is negligible in spatial coordinate system when the traveling speed is close to the peripheral speed of the rolls. After small equipment was made, a reference point on a solder sheet was observed with an optical microscope. Changes in sheet speed and equivalent strain rate were calculated from the measured displacement. It is found that equivalent strain rate takes a maximum in the roll bite in case of heavy reduction rolling.

Keywords : Rolling, Deformation, Kinematics

Corresponding Author : Hiroshi Utsunomiya (uts@mat.eng.osaka-u.ac.jp)

CV

Invited Speakers

Name	Affiliation	Title	Abstract	CV
Tea-Sung Jun	Incheon National University	Cold dwell fatigue of titanium alloys in aero-engine industry	Abstract Cold dwell fatigue of titanium alloys in aero-engine industry Tea-Sung Jun*1 1Incheon National University Cold dwell fatigue has long been a critical issue in aero-engine industry, because it significantly affects fatigue life typically in near-alpha titanium alloys at temperatures in the range of -40 to 200°C. The term ‘dwell fatigue’ describes the decrease in a component’s fatigue life time when exposed to continuous high mean stress while cruising, between the load ramping up at take-off and the load ramping down upon landing. Among the multiple factors affecting dwell fatigue, time-sensitive and rate-dependent deformation have been considered as critical factors in cold dwell fatigue. In this talk, I will be presenting the overview of dwell fatigue and the on-going experimental works on strain rate sensitivity and creep of Ti-6Al-2Sn-4r-2Mo and Ti-6Al-4V alloys. The presented approaches will show you a new exciting mechanistic insight into important deformation mechanisms, as well as opening up further studies of new alloy design. Keywords : Dwell fatigue; Titanium alloys; Deformation; Micromechanics Corresponding Author : Tea-Sung Jun (t.jun@inu.ac.kr)	CV
JaeHwang Kim	KITECH	Advanced characterization for cluster analysis using three dimensional atom probe in Al-Mg-Si alloy	Abstract Advanced characterization for cluster analysis using three dimensional atom probe in Al-Mg-Si alloy JaeHwang Kim*2, Jiwook Park4, Miyoung Lee3, Sara Song1 1Korea Institute of Industrial Technology, 2Korea Institute of Industrial Technology, University of Science & Technology, Korea Institute of Science and Technology, 3Korea Institute of Industrial Technology, Jeonbuk National University, 4Korea Institute of Industrial Technology, University of Science & Technology The strength of Al-Mg-Si alloys is dramatically increased because of the formation of precipitate. Due to their good age-hardening response, aluminum alloys have been used for automotive body panel. Atomic clusters are formed during low temperature aging natural aging. It is hard to understand the atomic arrangement of cluster since they do not have any crystal structure. Low temperature aging was carried out, and three dimensional atom probe was utilized to clarify the inter-atomic structure. Cluster identification algorithm such as the maximum separation method (MSM) was applied. Cluster analysis was conducted with the combination of several variables since cluster analysis is affected by the determination of user-defined parameters (Dmax and Nmin) in MSM. The clustering behavior is discussed based on the age-hardening phenomena. Keywords : Al-Mg-Si alloys, Age-hardening, Atomic clusters, Three dimensional atom probe Corresponding Author : JaeHwang Kim (raykim@kitech.re.kr)	CV
Myeong-Heom PARK	Kyoto University	Quantitative characterization of local deformation behavior in ferrite + martensite dual phase steels with different grain sizes by digital image correlation method	Abstract Quantitative characterization of local deformation behavior in ferrite + martensite dual phase steels with different grain sizes by digital image correlation method Myeong-heom Park*1, Akinobu Akinobu3, Stefanus Harjo2, Nobuhiro Tsuji1 1Department of Materials Science and Engineering, Kyoto University, 2J-PARC Center, Japan Atomic Energy Agenc, 3Research Center for Structural Materials, National Institute for Materials Science (NIMS) Low-carbon dual-phase (DP) steels, composed of ferrite and martensite, are widely used in the automotive industry due to their favorable balance of strength and ductility, as well as their high strain hardening capacity. Grain refinement in DP steels has been reported as an effective method to achieve both high strength and increased ductility, particularly in the post-uniform elongation region. However, the underlying mechanisms responsible for the enhancement of post-uniform elongation through grain refinement are not fully understood. In this study, we characterized the local deformation behavior and micro-void evolution using digital image correlation (DIC) combined with detailed scanning electron microscopy (SEM) observation of tensile-deformed microstructures. The coarse-grained DP specimen exhibited strong strain localization in the ferrite grains, with several large micro-voids observed in the necked region. In contrast, the fine-grained DP specimen displayed more homogeneous deformation, with only small micro-voids present. This significant difference in local deformation behavior may contribute to the observed variation in post-uniform elongation. Keywords : dual phase steel; plastic deformation; digital image correlation; local strain; micro void Corresponding Author : Myeong-heom Park (park.myeongheom.8r@kyoto-u.ac.jp)	CV
Nobuo Nakada	Institute of Science Tokyo	Anisotropic Cleavage Fracture Caused by Transformation-induced Internal Stresses in Martensitic Steels	Abstract Anisotropic Cleavage Fracture Caused by Transformation-induced Internal Stresses in Martensitic Steels Nobuo Nakada*1 1Institute of Science Tokyo The effect of microscopic internal stresses (Type-II) generated via martensitic transformation from austenite (A) to martensite (M) on {001}M cleavage fracture was investigated in as-quenched 0.1 mass%C–5.0 mass%Mn steel. Crystallographic orientation analysis using the electron backscatter diffraction technique revealed that cryogenic {001}M cleavage fracture predominantly occurred in mode I fracture during Charpy impact testing and that the Bain group, where martensite variants share the same Bain variant, acted as an effective unit to prevent fracture. It was also discovered that cleavage cracks preferentially propagate on (001)M rather than on (100)M within the Bain group, where (001)M is nearly parallel to (001)A in the Bain lattice correspondence ([-110]A // [100]M, [110]A // [010]M, (001)A // (001)M). Furthermore, using a combination of micro-scale focused ion beam and high-precision digital image correlation techniques, it was found that microscopic internal stresses developed anisotropically in each Bain group. The principal axes of these internal stresses corresponded to the <001>M coordinate axes in the Bain lattice correspondence, with the principal stress parallel to [001]M being significantly higher than the other two. After measuring the internal stresses, it was demonstrated that cleavage fracture behavior followed the effective normal stress in the normal direction of {001}M, which consisted of the resolved bending stress from the impact test and the anisotropic internal stress generated via martensitic transformation. This suggests that transformation-induced internal stresses from Bain strain contribute to the anisotropy of cleavage fracture in lath martensite. Keywords : Martensite, Cleavage fracture, Internal stress, Anisotropy Corresponding Author : Nobuo Nakada (nakada.n.aa@m.titech.ac.jp)	CV
Hyokyung Sung	Kookmin University	Influence of Zn on the Fracture Toughness of Al-Zn-Mg alloys	Abstract Influence of Zn on the Fracture Toughness of Al-Zn-Mg alloys Hyokyung Sung*1, Yong Hee Jo2, Hyeji Jung1, Seoyeon Jeon1, Hyunjoo Choi1, Hyoung-Wook Kim2 1Kookmin University, 2Korea Institute of Materials Science Balancing mechanical strength and fracture toughness has long been a key challenge in designing metallic materials. In this study, we examine how changes in Zn content affect the tensile properties and fracture behavior of Al-Zn-Mg-Cu alloys. As the Zn content increases, both yield strength and tensile strength improve, mainly due to enhanced precipitation hardening from a higher volume fraction of η′ phases. However, this gain in strength leads to a decrease in fracture toughness. The reduced toughness is linked to a smaller plastic zone near the crack tip and conditions that favor crack propagation. The high dislocation density caused by fine η′ precipitates contributes to this behavior, especially due to the local strain fields around the precipitates. These results show that Zn content plays a key role in managing the trade-off between strength and toughness, offering useful insights for designing high-performance Al-Zn-Mg-Cu alloys. Keywords : Al-Zn-Mg-Cu alloys, Tensile Strength, Fracture Toughness, Plastic Zone Corresponding Author : Hyokyung Sung (hyokyung@kookmin.ac.kr)	CV
Jin-yoo Suh	KIST	Creep behavior of ferritic/martensitic heat-resistant steel with Cu-addition	Abstract Creep behavior of ferritic/martensitic heat-resistant steel with Cu-addition Jin-Yoo Suh*1, Duhyun Kim1, Byeong-hyeon Lee1, Seong-hoon Kim2, Woo-sang Jung1, Dong-ik Kim1, Gyeong-ho Kim1, Seok Su Sohn4, Jong-ho Shin3, Tae-ho Lee2 1Korea Institute of Science and Technology, 2Korea Institute of Materials Science, 3Doosan Enerbility, 4Korea University This study aims to enhance the high-temperature properties and creep resistance of 10% Cr Ferritic/martensitic steels used in steam turbine rotors and blades in combined heat and power systems. By replacing Co with Cu, which performs a similar role but at a lower cost, an alloy was designed to improve high-temperature strength and maintain performance under prolonged exposure to elevated temperatures. Creep tests were conducted for the reference (Cu-free) and modified (Cu-added) steels at 630°C under various stress conditions (145–225 MPa) to evaluate the effect of Cu addition. The results showed that, as the applied stress increased from 145 to 225 MPa, the time to enter the tertiary creep stage decreased, and the minimum creep rate increased for both steels. Notably, the Cu-containing steel exhibited superior creep resistance for long-term creep under low stress conditions, especially at 145 MPa, where its life was increased up to 12,733 hours which is 14% improved compared to the Cu-free steel. Microstructural analysis using Electron Back-Scattered Diffraction (EBSD) revealed that the Cu-containing steel exhibited stable prior austenite grain size and better retention of martensite lath structure during long-term creep. Transmission electron microscopy confirmed that the Cu-rich precipitates played a significant role in delaying recovery by keeping the dislocation density still high. XRD data analysis using the Modified Williamson-Hall (MWH) and Modified Warren-Averbach (MWA) methods demonstrated that the dislocation density of the Cu-free steel decreased by 81%, while that of the Cu-containing steel decreased by only 66% after long-term creep. Overall, the addition of Cu delayed dislocation recovery and grain coarsening, thereby maintaining the high temperature strengthening effects and enhancing the creep resistance of the alloy. Keywords : Ferritic/Martensitic heat-resistant steel, Steam turbine, Rotor, Blade, Creep Corresponding Author : Jin-Yoo Suh (jinyoo@kist.re.kr)	CV
Seong-jun Park	KIMS	Prediction of the Distribution of Mechanical Properties in Austenitic FeMnAlC Lightweight Steels	Abstract Prediction of the Distribution of Mechanical Properties in Austenitic FeMnAlC Lightweight Steels Seong-Jun Park*1, Kyeong-Won Kim1, Jun Young Park1, Seong Hoon Kim1, Hyungkwon Park1 1Korea Institute of Materials Science Austenitic FeMnAlC lightweight steels are known as age-hardenable alloys. Before age hardening, these steels should undergo heat treatment for solutionization. After this heat treatment, the mechanical properties of lightweight steels may vary depending on the local thermal history during the cooling process. In this study, the effects of thermal history on the microstructure and mechanical properties of lightweight steels were investigated using austenitic FeMnAlC alloys. The average cooling rate was controlled experimentally, ranging from -0.053 °C/s to -337 °C/s. Under the slowest cooling condition, κ-carbides precipitated within austenite grains as well as at grain boundaries. In the case of a specimen with an Al composition of 12.8 wt%, β-Mn precipitated at the phase boundaries between D0₃ and austenite. The formation of κ-carbides and β-Mn resulted in a drastic decrease in impact absorbed energy and the occurrence of intergranular brittle fracture behavior. Finite element calculations were conducted to simulate the cooling of an industrial-scale slab of lightweight steels. Based on the calculated local thermal histories and experimental data obtained under various cooling conditions, the distribution of mechanical properties in the slab was estimated. Keywords : Lightweight steel, Cooling, κ-carbide, Mechanical properties Corresponding Author : Seong-Jun Park (hyega@kims.re.kr)	CV
Il-guk Jo	Dongeui University	Characterization of the Core-Rim Structure in TiC-Steel Composites Produced by the Liquid Pressing Infiltration Process	Abstract Characterization of the Core-Rim Structure in TiC-Steel Composites Produced by the Liquid Pressing Infiltration Process ILGUK JO*1, Seungchan Cho2 1Dong-Eui University, 2Korea Institute of Materials Science (KIMS) A titanium carbide (TiC)-reinforced steel composite was manufactured using the liquid pressing infiltration (LPI) method. These composites, featuring a high volume fraction of TiC reinforcement, had a density of less than 6.0 g/cm³. The findings revealed that a core-rim structure developed in the composite due to the partial dissolution of the TiC particles during the LPI process. The study explored how the dissolution of TiC particles influenced the microstructure and mechanical properties of the composite. The improved mechanical performance was attributed to efficient load transfer from the steel matrix to the TiC reinforcement, facilitated by strong interfacial bonding. This interfacial stability resulted from chemical bonding, which occurred due to the partial dissolution and subsequent precipitation of TiC during processing. To establish a link between the core-rim structure and the composite’s properties, nanoindentation was used to measure hardness (H) and Young’s modulus (E). Keywords : Lightweight, TiC-steel composite, Liquid pressing infiltration, Core-rim structure Corresponding Author : ILGUK JO (ijo@deu.ac.kr)	CV
Young-Rae Cho	Pusan National University	Mechanical Properties and Thermal Conductivity of Eco-Friendly Clad Metals for Industrial Applications	Abstract Mechanical Properties and Thermal Conductivity of Eco-Friendly Clad Metals for Industrial Applications Young-Rae Cho*1, Sung-Yong Mon1, Dong-Hui Lee1, Dong-Hyun Bae2 1Pusan National University, 2Korea Clad Tech. Co. Ltd. Eco-friendly clad metals are advanced layered composites that combine different metals to create unique properties, including enhanced mechanical strength and thermal conductivity, particularly in the thickness direction. These distinctive characteristics make them highly suitable for a wide range of applications across various industries. Thin-clad metals, in particular, are increasingly utilized in the sensor industry and battery industry. This paper focuses on the manufacturing technologies of clad metals, emphasizing their mechanical properties and the crucial role of their thermal conductivity in thickness direction, which optimizes performance in applications spanning automotive, electrical and electronics, construction, home appliances, medical devices, and architectural facades. In the automotive industry, lightweight nature, durability, and superior thermal conductivity of the clad metals contribute to reducing vehicle weight and improving fuel efficiency. In the electrical and electronics sector, the exceptional electrical properties, electromagnetic shielding capabilities, and thickness-direction thermal conductivity of clad metals are essential for high-performance circuit boards and connectors. In the construction industry, corrosion resistance and strength of the clad metals help extend the lifespan of building materials, ensuring structural stability, while their aesthetic appeal enhances both exterior and interior designs, particularly as building facades. In the home appliance industry, the high thermal conductivity in the thickness direction improves the efficiency of appliances that require effective heat management. Moreover, thin-clad metals, by combining the advantages of multiple metals, significantly improve sensor performance and durability. This presentation will delve into the key manufacturing technologies behind clad metals, with a particular focus on their mechanical properties and directional thermal conductivity, and will discuss the potential technological advancements and benefits they offer across a variety of industries, including the growing field of architectural applications. Keywords : clad metals, thermal conductivity, mechanical property, manufacturing technology, industrial application Corresponding Author : Young-Rae Cho (yescho@pusan.ac.kr)	CV
Wonmo Kang	Arizona State University	Axially bi-continuous graphene-metal composites for novel structural and electrical applications	Abstract Axially bi-continuous graphene-metal composites for novel structural and electrical applications Wonmo Kang*1 1Arizona State University Graphene offers extraordinary mechanical, electrical, and thermal properties. To fully exploit these advantages, current graphene-metal techniques commonly integrate small-scale graphene flakes with a bulk-scale metal matrix. However, this approach achieves very limited material enhancement, compared to the excellent properties of graphene, mainly due to the ineffective load transfer path between small-scale graphene and a metal matrix. In this talk, we present an innovative graphene-metal composite with an axially bi-continuous structure to address the current intrinsic challenges in the graphene-metal composite community. Two different metal matrices-nickel and copper-are used as a model to demonstrate significantly enhanced material performance with an emphasis on structural and electrical applications, respectively. For example, our axially bi-continuous graphene-nickel composite wires break a trade-off condition between mechanical strength and ductility, achieving remarkable increases in both strength (124%) and ductility (12%). Additionally, graphene-coated copper wires exhibit a 450% increase in current density limits and a 41% increase in electrical conductivity compared to pure copper. Our experimental and theoretical studies on the mechanisms behind these enhancements reveal that continuous graphene forms a direct mechanical and electrical load transfer path along the length of the wire and greatly improve the overall performance of the graphene-metal composites. We believe our work is crucial for the design of other high-performance graphene-metal composites and the development of advanced manufacturing techniques for high-throughput and scalable production. Keywords : graphene, metal, composite Corresponding Author : Wonmo Kang (wonmo.kang@asu.edu)	CV

07 VII. Computational Materials Science

Keynote Speakers

De-en Jiang

Vanderbilt Univ.

Amorphous Halides as Solid Electrolytes for All Solid-State Lithium Batteries

Abstract

Amorphous Halides as Solid Electrolytes for All Solid-State Lithium Batteries

De-en Jiang*1

1Vanderbilt University

Amorphous LiTaCl6 and LiNbCl6 have been shown recently to yield record-low activation energies of ion transport (< 0.2 eV) and remarkably high ion conductivity (> 10 mS/cm) for all solid-state lithium batteries. In this talk, I will discuss our recent work in applying machine-learning force fields to understand and predict superionic Li-ion transport in amorphous halides as solid-state electrolytes for all solid-state Li batteries, especially for low temperatures. We predict even better Li-ion transport in amorphous LiNb0.5Ta0.5Cl6 solid electrolyte, based on machine-learning force fields trained on-the-fly from ab initio molecular dynamics (AIMD). This approach allowed us to carry out AIMD-quality simulations up to nanosecond timescale, so that we can simulate Li-ion transport at ambient conditions. We validated our approach by obtaining highly accurate simulated activation energies of Li-ion transport in LiTaCl6 and LiNbCl6. This confirmation lent great confidence to our predictions. We predict that the activation energy of Li-ion transport will be as low as 0.144 eV and the ion conductivity will be as high as 15.7 mS/cm at room temperature for LiNb0.5Ta0.5Cl6. Both values will be a record for halide-based electrolytes and solid electrolytes in general. Li-ion mobility is found to correlate with the degree of anharmonic cation-anion coupling: LiNb0.5Ta0.5Cl6 shows the strongest coupling of low-frequency Li-ion modes with Cl-ion vibration modes. Despite the many similarities between Nb and Ta, this work demonstrates that when both are present, the synergy between Nb and Ta can lead to even higher superionic Li-ion conductivity in LiNb0.5Ta0.5Cl6 than in LiTaCl6 and in LiNbCl6.

Keywords : solid electrolytes; machine-learning force fields; halides; supersonic conductors; lithium ion

Corresponding Author : De-en Jiang (de-en.jiang@vanderbilt.edu)

CV

Invited Speakers

Name	Affiliation	Title	Abstract	CV
Kihyun Shin	Hanbat National Univ.	Facet-Dependent Doping Strategies for Optimizing PtNi-Based ORR Catalysts	Abstract Facet-Dependent Doping Strategies for Optimizing PtNi-Based ORR Catalysts Kihyun Shin1 1Hanbat National University With the depletion of fossil fuels and the growing demand for sustainable energy, fuel cells have emerged as a promising alternative. Among various electrocatalysts, Pt-based materials exhibit excellent ORR activity but suffer from high cost and limited reserves. To overcome these challenges, we investigated In-doped PtNi(111) and Mo-doped PtNi(211) systems using DFT calculations. In doping on PtNi(111) optimized OH adsorption and suppressed Ni dissolution, improving both activity and stability. In the same manner, Mo doping on PtNi(211) fine-tuned OH* adsorption, further enhancing ORR performance. The facet-dependent effects revealed that doping technique primarily improves stability and electronic properties on PtNi. These results highlight that facet engineering combined with selective doping provides an effective strategy for designing highly active and durable Pt-based catalysts, paving the way for next-generation fuel cell applications. With the depletion of fossil fuels and the growing demand for sustainable energy, fuel cells have emerged as a promising alternative. Among various electrocatalysts, Pt-based materials exhibit excellent ORR activity but suffer from high cost and limited reserves. To overcome these challenges, we investigated In-doped PtNi(111) and Mo-doped PtNi(211) systems using DFT calculations. In doping on PtNi(111) optimized OH* adsorption and suppressed Ni dissolution, improving both activity and stability. In the same manner, Mo doping on PtNi(211) fine-tuned OH* adsorption, further enhancing ORR performance. The facet-dependent effects revealed that doping technique primarily improves stability and electronic properties on PtNi. These results highlight that facet engineering combined with selective doping provides an effective strategy for designing highly active and durable Pt-based catalysts, paving the way for next-generation fuel cell applications. Keywords : DFT, Nanoparticle, Doping, Fuel Cell, ORR Corresponding Author : Kihyun Shin (kihyun@hanbat.ac.kr)	CV
Soonho Kwon	Caltech	Recombination Dynamics of Water Ions in finite water droplets: Adaptive QM/MM study	Abstract Recombination Dynamics of Water Ions in finite water droplets: Adaptive QM/MM study Soonho Kwon1, Prabhat Prakash1, Frances A. Houle2, William A. Goddard III*1 1California Institute of Technology, 2Lawrence Berkeley National Laboratory The recombination dynamics of water ions (OH- and H3O+) in nanoscale droplets using an adaptive quantum mechanical/molecular mechanical (QM/MM) calculations. We investigated droplets ranging from 100 to 18,000 water molecules, corresponding to diameters up to 10 nm, to elucidate the effects of spatial confinement on water dynamics, ion distribution, and recombination processes. The adaptive QM/MM detect proton hopping (Grotthuss process) to track ions and to define new QM/MM boundary by geometric partitioning at every time step. Our findings reveal that water self-diffusion significantly decreases in droplets with diameters below 2.2 nm, highlighting the impact of extreme confinement on molecular behavior. Interestingly, we found that the recombination is not primarily limited by droplet size or surface structure, but rather by the geometry of the water wire connecting the ions as they approach each other. This geometric factor can often prevent or delay recombination, even when ions are in close proximity. In droplets containing 1000 H2O molecules, we observed that ions spend approximately 50% of their time on the surface and within 0.5 nm beneath it, with hydroxide ions showing a slight preference for surface residence. The recombination process in these nanoscale environments occurs on average at 400 ps for 1000 H2O droplets and 1 ns for 3000 H2O droplets. Our research also revealed the interplay between Grotthuss and vehicular diffusion mechanisms both inside the droplet and on its surface. In bulk water, the diffusion constants of hydronium and hydroxide increase by 3.4-fold and 3.0-fold, respectively, when proton hopping is allowed, compared to pure vehicular motions. These findings provide crucial insights into the reaction microenvironments present in nanoscopic water droplets, with significant implications for understanding confined water systems in various scientific and technological applications, including fuel cells, biological cellular components, and catalytic systems. Keywords : Ions, Grotthuss process, Recombination, QM/MM Corresponding Author : William A. Goddard III (wagoddard3@gmail.com)	CV
Liang Zhang	Tsinghua Univ.	Machine Learning Accelerated Design of Catalysts for the Sustainable Hydrogen Future	Abstract Machine Learning Accelerated Design of Catalysts for the Sustainable Hydrogen Future Liang Zhang*1 1Tsinghua University; Beijing Huairou Laboratory Catalysts play a crucial role in advancing sustainable hydrogen future, by reducing the loss during the conversion of diverse energy formats, thereby enhancing the efficiency and viability of hydrogen production and utilization processes. The multicomponent alloy catalysts not only effectively reduce the usage of precious metals but also significantly expand the compositional space for material design, providing diverse catalytic active sites. The chemical ordering of alloy catalysts, i.e. atomic arrangement of constituent elements is crucial for tuning the activity, selectivity, and stability of catalysts. By optimization of the chemical ordering of alloy catalysts, they can exhibit superior performance compared to single-component materials. In this presentation, I will mainly introduce recent work from our research group on establishing structure-performance relationships of alloy catalysts from the perspective of chemical ordering, as well as the optimization methods for catalyst atomic arrangement and their applications in hydrogen energy and fuel cells. The aforementioned work established structure-performance correlation models for different types of multicomponent catalytic materials at the molecular atomic scale, providing new insights for the design of related nanocatalytic materials. References [1] Yin, P.; Niu, X.; Li, S. Bin; Chen, K.; Zhang, X.; Zuo, M.; Zhang, L.; Liang, H. W. Nat. Commun. 2024, 15, 415. [2] Zhang, X.; Wang, C.; Chen, K.; Clark, A. H.; Hübner, R.; Zhan, J.; Zhang, L.; Eychmüller, A.; Cai, B.; Adv. Mater. 2023, 35 (14), 2211512. [3] Tang, T.; Liu, X. Z.; Luo, X.; Xue, Z.; Pan, H. R.; Fu, J.; Yao, Z. C.; Jiang, Z.; Lyu, Z. H.; Zheng, L.; Su, D.; Zhang, J. N.; Zhang, L.; Hu, J. S. J. Am. Chem. Soc. 2023, 145 (25), 13805–13815. Keywords : Machine Learning, Catalysts, DFT, Alloy Corresponding Author : Liang Zhang (zhangbright@tsinghua.edu.cn)	CV
Penghao Xiao	Dalhousie University	Kinetic simulation of electrochemical degradation: from LiNiO2 cathode capacity decay to NiCr aqueous corrosion.	Abstract Kinetic simulation of electrochemical degradation: from LiNiO2 cathode capacity decay to NiCr aqueous corrosion. Penghao Xiao*1 1Dalhousie University Materials in electrochemical environments experience accelerated degradation due to the inherently non-equilibrium nature of these systems. In functional materials such as Li-ion battery electrodes, degradation leads to capacity loss over cycles, while in structural materials like alloys, aqueous corrosion progressively weakens mechanical properties. Both processes have significant economic and technological implications. In this talk, I will present our recent progress in simulating long-time-scale kinetics of materials degradation under electrochemical conditions. We introduce a lattice-based atomistic simulation framework from first principles, that integrates multiple kinetic processes without empirical parameters. This approach enables us to uncover the evolving rate-limiting steps without preconceived assumptions. By reaching time scales of milliseconds and beyond, our simulations allow direct comparison with experiments. I will discuss two key examples: 1. High-Ni layered oxide cathodes – These materials offer high energy density but suffer from significant capacity loss during cycling, a phenomenon that remains poorly understood, limiting further improvements. Using LiNiO₂ as a model system, our simulations successfully reproduce both the first-cycle irreversible capacity loss at the end of discharge and the sluggish kinetics of the H2-H3 phase transition at the end of charge. After repeated cycling, we find that a surface-densified phase forms, suppressing H3 phase nucleation and severely hindering delithiation when Li content falls below 25%, while lithiation remains unaffected. These findings are in good agreement with recent experimental observations. 2. Aqueous corrosion of NiCr alloys – To simulate surface oxide evolution, we introduced a moving boundary condition, allowing us to track oxide thickness variation alongside composition changes. The predicted oxide behavior as a function of voltage, temperature, and pH aligns well with experimental characterizations. Furthermore, we uncover a new oxide growth mechanism driven by dissolution and reprecipitation in certain voltage range, providing fresh insights into surface structure reconstruction under electrochemical conditions. Keywords : DFT, KMC, cluster expansion, Li-ion battery, corrosion, atomistic kinetics Corresponding Author : Penghao Xiao (penghao.xiao@dal.ca)	CV
YongJoo Kim	Korea Univ.	Active learning approach in designing entropy alloy nanocatalyst	Abstract Active learning approach in designing entropy alloy nanocatalyst YongJoo Kim*1 1Korea University Searching for an optimal component and composition of multi-metallic alloy catalysts, comprising two or more elements, is one of the key issues in catalysis research. Due to the exhaustive data requirement of conventional machine-learning (ML) models and the high cost of experimental trials, current approaches rely mainly on the combination of density functional theory and ML techniques. In this study, a significant step is taken toward overcoming limitations by the interplay of experiment and active learning to effectively search for an optimal component and composition of multi-metallic alloy catalysts. The active-learning model is iteratively updated using by examining electrocatalytic performance of fabricated solid-solution nanoparticles for the hydrogen evolution reaction (HER). An optimal metal precursor composition of Pt0.65Ru0.30Ni0.05 exhibits an HER overpotential of 54.2 mV, which is superior to that of the pure Pt catalyst. This result indicates the successful construction of the model by only utilizing the precursor mixture composition as input data, thereby improving the overpotential by searching for an optimal catalyst. This method appears to be widely applicable since it is able to determine an optimal component and composition of electrocatalyst without obvious restriction to the types of catalysts to which it can be applied. Keywords : active learning, catalyst, entropy alloy Corresponding Author : YongJoo Kim (cjyjee@korea.ac.kr)	CV
Joonhee Kang	Pusan National Univ.	Machine Learning Interatomic Potentials for Energy Materials Design	Abstract Machine Learning Interatomic Potentials for Energy Materials Design Joonhee Kang*1 1Pusan National University Machine learning (ML) plays a crucial role in analyzing and predicting the physical and chemical properties of materials by utilizing large-scale databases. As nanoscale precision becomes increasingly important in materials science and engineering, the need for ML-driven predictions of atomic-level behavior is growing. Theoretical methods such as density functional theory (DFT) can provide insights into nanostructure properties but are constrained by high computational costs and applicability only to simple conditions. Nonetheless, DFT studies have demonstrated that structural information, including atomic arrangement and coordination number, is key to accurately determining physicochemical properties. Therefore, developing a force field (FF) capable of efficiently and accurately predicting nanoscale structural changes is essential. This presentation introduces ML-based force fields (ML-FFs) for nanomaterials, utilizing high-dimensional neural network potentials (HDNNPs), Gaussian process (GP), and a universal potential trained on a database generated from DFT calculations and ab-initio molecular dynamics (AIMD) simulations. This ML-FF approach, which balances computational efficiency with precision, aims to provide insights into physical properties and offer design strategies for high-performance materials. Keywords : Machine learning, Density functional theory, Molecular dynamics Corresponding Author : Joonhee Kang (j.kang@pusan.ac.kr)	CV
Woosun Jang	Yonsei Univ.	Small Dataset Machine-Learning for Multicomponent Alloy Design	Abstract Small Dataset Machine-Learning for Multicomponent Alloy Design Woosun Jang*1 1Yonsei University Striving for a sustainable energy future, researchers have actively explored the design of efficient photocatalysts for water splitting by tailoring their band properties. One promising strategy for band engineering in active photocatalysts is the introduction of multicomponent alloys. However, the vast number of possible configurations in multicomponent alloys poses a significant challenge for both experimental and theoretical screening across this complex material space. This challenge creates an opportunity for machine learning (ML) techniques to accelerate the discovery of novel multicomponent alloy materials. Typically, ML approaches require a large and accurate database of material properties, which often demands extensive computational or experimental resources. However, such large databases are either unavailable or only partially available for unexplored novel materials. Here, we present an effective strategy for designing multicomponent alloys without relying on large databases, exemplified by the ZnTe-based alloy system. This approach outlines and proposes strategies for identifying optimal ZnTe-based multicomponent alloys specifically tailored for photoassisted water-splitting applications, while minimizing and optimizing the need for high-level computational calculations. Keywords : Materials Discovery, Machine Learning, Small Dataset Corresponding Author : Woosun Jang (woosunjang@yonsei.ac.kr)	CV
Zhenghao Wu	Xi'an Jiaotong-Liverpool University	Learning Accurate and Transferable Force Fields for Physical Property Predictions of Organic Liquids	Abstract Learning Accurate and Transferable Force Fields for Physical Property Predictions of Organic Liquids Zhenghao Wu*1 1Xi'an Jiaotong Liverpool University Accurate and transferable force fields for molecular simulations of organic liquids remain challenging due to the complex interplay of conformational and chemical diversity. Here, we introduce a general framework for developing Neural network Potentials for Liquid Simulations (NPLS) across a wide conformational space for organic systems . After curating an extensive experimental dataset, we assess NPLS's accuracy on established benchmarks and advanced simulations of more than 200 different types of alkanes. NPLS combines stability and speed, providing an out-of-the-box tool for near-quantitative simulations of thermodynamics, dynamics, and phase transitions for organic liquids. This framework is potentially shifting the paradigm for force-field development of liquids, offering a scalable, data-efficient pathway to simulate complex organic systems with quantum accuracy, bridging QM-level precision and classical MD scalability for a broad range of applications in drug designs and materials developments. Keywords : Machine Learning, Force Field, Organic Liquids, Molecular Dynamics Corresponding Author : Zhenghao Wu (zhenghao.wu@xjtlu.edu.cn)	CV

08 VIII. Semiconductor Thin Films, Materials and Devices

Keynote Speakers

Bharat Jalan

University of Minnesota

High-Mobility, Deep-Ultraviolet Transparent Conducting SrSnO₃ Films with Room-Temperature Mobility Exceeding 140 cm2/Vs

Abstract

High-Mobility, Deep-Ultraviolet Transparent Conducting SrSnO₃ Films with Room-Temperature Mobility Exceeding 140 cm2/Vs

Bharat Jalan*1

1University of Minnesota

Exploration and advancement in ultra-wide bandgap (UWBG) semiconductors are essential for the development of next-generation high-power electronics and deep-ultraviolet (DUV) optoelectronics. In this study, we implemented a thin heterostructure design to enhance conductivity, leveraging the low electron mass and relatively weak electron-phonon coupling of the materials, while maintaining high transparency through atomically thin films. Using a SrSnO3/La:SrSnO3/GdScO3 (110) heterostructure and electrostatic gating, we successfully separated charge carriers in SrSnO3 from dopants, resulting in phonon-limited transport behavior in strain-stabilized tetragonal SrSnO3. This approach enabled modulation of carrier density from 1018 cm-3 to 1020 cm-3, achieving room-temperature mobilities between 40 and 140 cm2V-1s-1. First-principles calculations of phonon-limited mobility closely aligned with experimental results, suggesting the potential for even higher mobilities with increased electron density. Additionally, the heterostructure exhibited 85% optical transparency at a wavelength of 300 nm. I will discuss potential of heterostructure design in transparent UWBG semiconductor technologies, particularly for DUV applications.

Keywords : Semiconductor, UV applications, MBE, epitaxy, thin films, electronic transport, Gating

Corresponding Author : Bharat Jalan (bjalan@umn.edu)

CV

Daniel Gall

Rensselaer Polytechnic Institute

New materials for high-conductivity interconnects

Abstract

New materials for high-conductivity interconnects

Daniel Gall*1

1Rensselaer Polytechnic Institute

A major challenge for the continued downscaling of integrated circuits is the resistivity increase of interconnect lines and vias with decreasing dimensions, limiting power efficiency and causing the interconnect delay to exceed the gate delay. This resistivity increase is due to diffuse electron scattering at surfaces and grain boundaries and leads to, for example, a 10-fold resistance increase for 10-nm-wide Cu lines. This talk summarizes our search for alternative interconnect materials that have the potential to outperform Cu. These include metals with a small electron mean free path to render electron scattering at surfaces and grain boundaries negligible, electropositive metals with spherical Fermi surfaces which minimize surface charge transfer and maximize electron transmission at grain boundaries, and anisotropic compounds with preferential transport along the wire direction.

Keywords : interconnects, resistivity,

Corresponding Author : Daniel Gall (galld@rpi.edu)

CV

Invited Speakers

Name	Affiliation	Title	Abstract	CV
Gang Qiu	University of Minnesota	One-dimensional van der Waals tellurium for Ultra-scaled CMOS and quantum applications	Abstract One-dimensional van der Waals tellurium for Ultra-scaled CMOS and quantum applications Gang Qiu*1 1University of Minnesota, Twin Cities Since the debut of Moore’s Law in 1965, the cadence of semiconductor manufacturing has been governed by this empirical observation. It is evident that the downsizing trend of transistors cannot be sustained forever. The latest generations of silicon-based CMOS devices have had to overcome some serious challenges, such as power dissipation, reliability, and mobility degradation. The semiconductor industry is starting to cast hope onto two-dimensional (2D) material platforms as an alternative solution beyond silicon to extend the long-living Moore’s Law. These 2D materials feature interlayer van der Waals (vdW) forces between atomic sheets of covalently bonded atoms. However, little has been explored about one-dimensional (1D) vdW materials, which hold great potential for the miniaturization of CMOS logic applications. In this talk, we discuss a new type of 1D van der Waals semiconductor: single-element tellurium, as a promising candidate for the ultimate scaling of high-performance CMOS devices. I will present the material growth, doping strategy, device scaling, and prototype CMOS logic gates based on the 2D thin film and 1D nanowire form. The material exhibits desirable properties and outstanding electrical performance, including high mobility for both electrons and holes, low-contact resistance, and air stability, etc., making it suitable for next-generation gate-all-around transistors. In addition, the topological quantum transport behavior stemming from its unique chiral crystal structure and the related implications for quantum technologies will also be briefly discussed towards the end. Keywords : tellurene, 1D van der Waals, CMOS, Quantum device Corresponding Author : Gang Qiu (gqiu@umn.edu)	CV
Hiroshi Amano	Nagoya University	TBD
Zongliang Huo	China Academy of Science	TBD
Chanyoung Yoo	Hongik University	Atomic Layer Deposition of Chalcogenide Materials for Futuristic Semiconducting Devices	Abstract Atomic Layer Deposition of Chalcogenide Materials for Futuristic Semiconducting Devices Chanyoung Yoo*1 1Hongik University Despite extensive research and the availability of commercial memory products based on chalcogenide materials, such as phase-change memory (PCM) and selector-only memory (SOM), significant challenges remain in achieving fully functional, high-density, and low-power memory solutions. One major obstacle is the limitation of current memory architectures, which primarily rely on crossbar arrays (CBA) that struggle to meet the demands for ultra-high density and lower cost per bit. Vertical architectures, such as those demonstrated by V-NAND technology with over 200-layer stacks, offer a proven pathway toward highly integrated vertical-type crossbar array (V-CBA) memory. However, fabricating conformal phase-change and ovonic threshold switch (OTS) selector layers on etched sidewalls in these vertical structures necessitates the use of Atomic Layer Deposition (ALD). ALD ensures uniform coverage of chalcogenide-based films but requires precise selection of reactive cation and anion precursors. This presentation introduces strategies for depositing chalcogenide materials using various precursors and modified processes, focusing on the underlying reaction mechanisms. It addresses challenges in depositing multicomponent chalcogenide films, including unfavorable chemical interactions between the precursors and predeposited films. Additionally, a sacrificial ALD approach for controlling of the crystallographic orientation of the crystalline chalcogenide films is introduced. Finally, the presentation highlights the deposition of oriented Sb2Te3/GeTe superlattice films, demonstrating their potential for next-generation high-density memory applications. Keywords : Atomic Layer Deposition, Chalcogenide Materials Corresponding Author : Chanyoung Yoo (cyyoo@hongik.ac.kr)	CV
Taehwan Moon	Ajou University	Ferroelectric Tunnel Junctions for Neuromorphic Computing	Abstract Ferroelectric Tunnel Junctions for Neuromorphic Computing Taehwan Moon*1 1Ajou University Memristor crossbar arrays can perform matrix-vector multiplication, which are critical to AI computation, in a time- and energy-efficient way. However, as the size of the crossbar array increases, the error in the matrix-vector multiplication due to parasitic resistance components in the transmission line increases. This problem can be mitigated by utilizing filament-free memristors, where the resistance of the individual elements is high enough that parasitic resistance is negligible. Ferroelectric tunnel junctions are promising as artificial synaptic devices due to their extremely fast operation speed and excellent data retention compared to other filament-free memristors. In this talk, we will explore the effect of electrons injected at the ferroelectric/dielectric interface on the behavior of ferroelectric tunnel junctions and present engineering solutions to overcome the nonlinear synaptic weight update characteristics of ferroelectric tunnel junctions through circuit and structural improvements. Keywords : Ferroelectric, Neuromorphic Corresponding Author : Taehwan Moon (taehwanm@ajou.ac.kr)	CV
Min Ju Kim	Dankook University	Functional Polymeric Thin Films via iCVD Process for Advanced BEOL/PKG in Semiconductor	Abstract Functional Polymeric Thin Films via iCVD Process for Advanced BEOL/PKG in Semiconductor Min-Ju Kim*1 1Dankook University Polymeric materials offer high applicability in advanced fields such as semiconductors, as their thermal, mechanical, and electrical properties can be freely adjusted through modifications and combinations of various functional groups. However, since polymer materials are primarily formed using solution-based processes, their application in high-tech fields like semiconductors presents challenges. Initiated chemical vapor deposition (iCVD) is emerging as a next-generation semiconductor processing technology, as it enables the synthesis of high-purity functional polymer thin films at room temperature without solvents. This is achieved by inducing free-radical polymerization reactions in the vapor phase. Using the iCVD process, polymer thin films with network or bridge structures containing siloxane functional groups can be synthesized. A representative example is the pV3D3 polymer, which exhibits low dielectric (low-k) properties essential for semiconductor interconnect structures (BEOL). This is due to the symmetrical molecular structure and the shielding effect of methyl groups around the functional units, which reduce the polymer's internal dipole response to external electric field changes. Moreover, by incorporating monomers containing C-F bonds to form a copolymer, leakage current can be suppressed while further lowering the dielectric constant. Similar to BEOL, iCVD also holds significant potential for applications in semiconductor packaging (PKG). PKG, which can be considered a scaled-up version of BEOL structures, requires dielectric materials to play a crucial role in connecting and isolating signals between chips. Additionally, as PKG trends toward 3D stacking, ensuring stability requires dielectric materials with softer mechanical properties. For large-area implementation of dielectric thin films in PKG while minimizing chip degradation, it is essential to form these films at low temperatures—an area where iCVD technology is particularly well-suited. If iCVD can provide polymeric dielectric materials that meet the requirements of Hybrid Bonding, TSV Coating, Interposers, and Redistribution Layers, it could bring a significant breakthrough in PKG technology. Keywords : iCVD, Polymer, BEOL, PKG, ULK, Hybrid Bonding Corresponding Author : Min-Ju Kim (minju9062@dankook.ac.kr)	CV
In-Hwan Baek	Inha University	ALD-Based Fabrication of High-Quality n/p-Type Oxide Semiconductor Channels for Stackable CMOS system	Abstract ALD-Based Fabrication of High-Quality n/p-Type Oxide Semiconductor Channels for Stackable CMOS system In-Hwan Baek1, IN-HWAN BAEK*1 1Inha University The atomic layer deposition (ALD) process has been used for the core technology of the latest DRAM, NAND, and Logic devices. These devices exploit the advantages of ALD processes such as superior step coverage, in-wafer uniformity, and thickness controllability. The demand for ALD processes is still highly increasing since lateral shrinking & vertical stacking trends of the latest devices. However, ALD processes that are being practically applied in the current semiconductor industry are mostly limited to dielectric thin films and electrode applications. To implement VCAT-based DRAM and monolithic 3-D devices (M3D), high-performance semiconducting thin film for transistors also need to be developed via ALD. The absence of suitable p-type and n-type semiconducting thin films deposited by ALD processes has been a major challenge that the semiconductor industry faces. Here, we demonstrated a high-performance thin-film CMOS system by adopting atomic layer deposited n-type and p-type semiconducting materials. The process temperature for fabricating CMOS devices was kept below 300°C, eliminating the thermal budget issue, which is the biggest hurdle in M3D fabrication. These notable results were achieved through phase engineering enabled by the novel precursor and effective surface/interface control. This development of complementary n-type and p-type semiconducting thin films using the ALD process is expected to pave the way for the vertical stacking of thin-film CMOS transistors and next-generation memory applications. Keywords : ALD, Oxide semiconductor, M3D Corresponding Author : IN-HWAN BAEK (baek@inha.ac.kr)	CV

09 IX. Emerging Materials and Devices in Advanced Biomedical Application

Keynote Speakers

Dong June Ahn

Korea University

Nanotechnology for Cell Cryopreservation

Abstract

Nanotechnology for Cell Cryopreservation

Dong June AHN*1

1Korea University

Water freezing is a commonly observed natural phenomenon; however, ice growth and recrystallization can critically damage living organisms. Nature has evolved to produce antifreeze proteins to survive this freezing threat. Their specific amino acid sequence has been widely accepted to play a critical role in binding to ice, which can result in antifreeze activity when the Kelvin effect is dominant at the ice interface. On the contrary, ice-binding surfaces can also lead to heterogeneous ice nucleation when the appropriate chemical and dimensional constraints meet. Ice nucleation proteins possess relatively large ice-binding surfaces and thus facilitate the organization of surrounding water molecules in an ice-like lattice that could promote ice nucleation. Both phenomena, which require ice-binding characteristics in common, demand distinct design protocols, and thus active mimetic materials have been developed by tailoring them for respective purposes. In this presentation, we will address our recent achievements on cell cryopreservation based on strategic design and control of water-ice interfaces created by unique nano-assemblies working at subzero temperatures.

Keywords : Cell, Cryopreservation, Antifreeze, Nanomaterials

Corresponding Author : Dong June AHN (ahn@korea.ac.kr)

CV

Dong-Hyun Kim

Northwestern University

Dynamic Materials-Enabled Combinational Cancer Immunotherapy

Abstract

Dynamic Materials-Enabled Combinational Cancer Immunotherapy

Dong-Hyun Kim*1

1Northwestern University

Dynamic materials, including nanoparticles and stimuli-responsive materials, have a great potential for the future of cancer medicine. Various clinical cancer diagnosis, monitor, and therapeutics can be catalyzed with those dynamic materials. The enhanced performance of materials enabled combinational immunotherapy will suggest an innovative solution in cancer treatment. Recent efforts to develop dynamic materials for combinational immunotherapy applications will be presented in this talk.

Keywords : dynamic materials; cancer; immunotherapy;nanomedicine

Corresponding Author : Dong-Hyun Kim (dhkim@northwestern.edu)

CV

Invited Speakers

Name	Affiliation	Title	Abstract	CV
Iksung Cho	Kyushu University	Engineering the residence time and immune cloaking of mesenchymal stromal cells with microgel-coating to overcome chronic fibrotic remodeling	Abstract Engineering the residence time and immune cloaking of mesenchymal stromal cells with microgel-coating to overcome chronic fibrotic remodeling Iksung Cho*1, Jae-Won Shin2, Masaru Tanaka1 1Kyushu University, 2University of Illinois at Chicago Pulmonary fibrosis, affecting thousands worldwide, remains challenging to treat due to limited therapeutic options and rapid clearance of delivered cells. Mesenchymal stromal cells (MSCs) offer promise through the secretion of paracrine factors that modulate inflammation and promote tissue repair. However, MSCs often fail to persist in the lungs long enough to exert their full therapeutic effects. To address this limitation, thin gel encapsulation strategies have been developed using soft, conformal alginate-based microgels functionalized with immunomodulatory cues, such as zwitterionic polymers and a CD47-derived agonist peptide. These coatings inhibit nonspecific protein adsorption and leverage the natural “marker-of-self” interaction with macrophages, thereby evading clearance in the lungs. Mathematical modeling suggests that extending MSC residence time is critical for the cells to integrate local inflammatory cues and produce anti-fibrotic signals like TNFα. In vivo experiments confirm that reducing alveolar macrophage activity, either through clodronate treatment or immune-evasive gel coatings, significantly improves MSC retention in both normal and fibrotic lungs. Single-cell RNA sequencing further highlights a transitional CD11bloMHC-IIhi macrophage subpopulation that appears to mediate the reparative response when immune-cloaked MSCs are delivered. By combining immune cloaking and the strategic presentation of local signals encoded in the gels, this approach not only accelerates resolution of transient fibrotic injury but also reverses persistent fibrosis induced by repeated lung damage. The ability to fine-tune and prolong MSC residence time presents a powerful platform for developing a “living pharmacy” that enables long-term, targeted tissue remodeling in chronic lung diseases. Keywords : Single cell encapsulation, Microgel, Immune cloaking, Microfluidic device, Lung fibrosis Corresponding Author : Iksung Cho (iksung_cho@ms.ifoc.kyushu-u.ac.jp)	CV
Su Chin Heo	University of Pennsylvania	Tunable Extracellular Matrix-Based Hydrogel Systems for Zone-Specific Musculoskeletal Repairs	Abstract Tunable Extracellular Matrix-Based Hydrogel Systems for Zone-Specific Musculoskeletal Repairs Su Chin Heo*1, Se-Hwan Lee1 1University of Pennsylvania Fibrous connective tissues, such as the meniscus, exhibit distinct properties across different zones, requiring zone-specific strategies for effective repair and regeneration. For this, we have investigated the potential of decellularized meniscus extracellular matrix (DEM) to regulate cell behavior and enhance tissue formation. However, the relationship between the biochemical and mechanical properties of DEM during development and their effects on cellular responses is not fully understood. Thus, this study explores how age-dependent DEM, with tuned stiffness, influences cellular behavior, accompanied by a comprehensive proteomic analysis. To address zone-specific meniscus tears, injectable materials tailored to individual zones are necessary. To this end, we have developed stiffness-tunable, DEM-based injectable hydrogel systems combined with methacrylate hyaluronic acid (MeHA). We examined how these hydrogels influence cell behavior in vitro, providing insights into their therapeutic potential. For this, fetal and adult bovine menisci were decellularized, and pre-gels of 'soft' (35% modified) and 'stiff' (100% modified) MeHA were synthesized. Each DEM was blended with soft, stiff, or soft/stiff MeHA to create stiffness-tunable hydrogels. Proteomic analysis revealed distinct profiles between fetal and adult DEM, with an increased presence of fibrochondrogenesis-related genes in adult DEM, suggesting that age-dependent processing affects the ECM composition of the meniscus. Additionally, the stiffness-tunable DEM-based MeHA hydrogel systems offer precise control over the stiffness of the hydrogels. Stiff DEM-MeHA hydrogels upregulate fibrochondrogenic gene expression, while soft and soft/stiff DEM-MeHA hydrogels promote chondrogenic gene expression in mesenchymal stem cells. These findings emphasize the importance of both biochemical and mechanical cues for effective meniscus repair, particularly for zone-specific strategies. Ongoing in vivo animal studies are investigating the therapeutic potential of these findings. Keywords : Meniscus repair, Age-dependent extracellular matrix, Methacrylate hyaluronic acid, Stiffness tunable Hydrogel Corresponding Author : Su Chin Heo (heosc@upenn.edu)	CV
Min Hee Kim	Kyungpook National University	TBD		CV
Dong-Wook HAN	Pusan National University	Versatile and Marvelous Potentials of 2D Nanomaterials for Tissue Engineering & Regeneration	Abstract Versatile and Marvelous Potentials of 2D Nanomaterials for Tissue Engineering & Regeneration Dong-Wook HAN*1 1Pusan National University The emergence of 2D nanomaterials (2D NMs), which was initiated by the isolation of graphene in 2004, revolutionized various biomedical applications, including bio-imaging and -sensing, drug delivery, and tissue engineering (TE), owing to their unique physicochemical, electrical, mechanical and biological properties. Building on the success of graphene, a novel class of multi-elemental 2D NMs, known as MXenes, recently emerged, offering distinct advantages in the fields of TE and regenerative medicine. In this presentation, I focus on the comparison of graphene and MXene materials for use in fabricating TE scaffolds. After a brief introduction to the basic physicochemical properties of these materials, recent representative studies are classified in terms of the engineered tissue, i.e., bone, muscle, and skin tissues. I analyze several methods of improving the clinical potential of MXene-laden scaffolds using state-of-the-art fabrication technologies and innovative biomaterials. Despite the considerable advantages of MXene materials, critical concerns, such as biocompatibility, biodistribution and regulatory challenges, should be considered. This presentation and collaborative efforts should advance the field of MXene-based TE and enable innovative, effective solutions for use in future tissue regeneration. Keywords : 2D nanomaterials, graphene, MXene, tissue engineering, regenerative medicine Corresponding Author : Dong-Wook HAN (nanohan@pusan.ac.kr)	CV
Jaehyuk Kim	Pusan National University	Structurally Engineered Silica Nano/Microstructures for Advanced Biomedical Applications	Abstract Structurally Engineered Silica Nano/Microstructures for Advanced Biomedical Applications Jaehyuk Kim*1 1Pusan National University Silica nanoparticles have been extensively studied in the biomedical field due to their chemical stability, tunable surface properties, and biocompatibility. While the Stöber method is widely used for synthesizing uniform solid spherical silica particles, increasing attention has been given to the development of silica nano/microparticles with diverse shapes (e.g., rods, spikes) and complex architectures (e.g., hollow and yolk–shell structures). These structural variations offer distinct advantages, such as increased loading capacity, anisotropic behavior, and multifunctionality, which are particularly beneficial for applications in drug delivery, photothermal therapy (PTT), and photodynamic therapy (PDT). In this presentation, we introduce synthetic strategies for fabricating silica particles with tailored shapes and hierarchical structures, as well as characterization results that reveal their morphological and physicochemical features. We further explore their potential in biomedical applications, emphasizing how structural design can enhance functionality and therapeutic efficacy. Given the versatility of silica and the growing demand for efficient and targeted therapeutic platforms, structurally innovative silica particles are expected to remain a significant area of research in the future. Keywords : Silica nano/micro-particle, Synthesis, Biomedical application Corresponding Author : Jaehyuk Kim (jaehyuk.kim@pusan.ac.kr)	CV
Wooram Park	Sungkyunkwan University	Dual-Functional Hafnium Oxide Nanoplatform: Combining High-Z Radiosensitization with Bcl-2 Silencing for Enhanced Cancer Radiotherapy	Abstract Dual-Functional Hafnium Oxide Nanoplatform: Combining High-Z Radiosensitization with Bcl-2 Silencing for Enhanced Cancer Radiotherapy Wooram Park*1 1Sungkyunkwan University Cancer radiotherapy efficacy is limited by insufficient radiosensitization and tumor radioresistance. We developed a dual-functional hafnium oxide (HfO₂) nanoplatform that combines high-Z radiosensitization with Bcl-2 gene silencing. The nanoplatform was created by modifying HfO₂ nanoparticles with polyethyleneimine for efficient siRNA delivery while preserving radiosensitizing properties. Physicochemical analysis confirmed successful modification and stable siRNA complexation. The nanoplatform enhanced reactive oxygen species generation and DNA damage while delivering Bcl-2 siRNA to suppress anti-apoptotic mechanisms. In vitro studies showed synergistic enhancement of radiation-induced cell death through increased γ-H2AX expression and apoptotic populations. In a CT26 murine colon cancer model, local irradiation (6 Gy, single dose) was delivered to tumors 4 hours post-injection, with the rest of the body protected by lead shielding. This treatment achieved 80% tumor growth inhibition while maintaining good biocompatibility. Mechanistic studies confirmed effective Bcl-2 downregulation and enhanced DNA damage in tumor tissues. This approach presents a promising strategy for improving radiotherapy by simultaneously enhancing radiosensitization and suppressing radioresistance. Keywords : Hafnium oxide; Radiosensitization; siRNA delivery; Bcl-2 silencing; Cancer radiotherapy, Nanomedicine Corresponding Author : Wooram Park (parkwr@skku.edu)	CV
Kyobum Kim	Dongguk university	Biomaterial-mediated ex vivo Cell Surface Engineering: Augmentation of Membrane-dependent Signaling Cascade	Abstract Biomaterial-mediated ex vivo Cell Surface Engineering: Augmentation of Membrane-dependent Signaling Cascade Kyobum Kim*1 1Dongguk University Suitable manipulation of single cell surfaces could augment the recognition with target counterparts via membrane-dependent interactions. By facilitating dynamics of receptor-ligand interactions in NK-cancer interfaces, infused immune cells are able to recognize target tumor cell population, and thereby enhanced anticancer efficacy of surface-engineered NK cells and subsequent tumor suppression are successfully achieved. Moreover, same platform technique could be also applied toward stem cell surface modulation for various disease treatments. In this research, biomaterial-mediated ex vivo cell surface engineering is introduced for the membrane decoration of [1] cancer-targeting moieties onto NK cells as well as [2] signal-activating moieties on MSC surfaces. Upon, a variety of design strategies of membrane-presentable modules have been developed to improve signaling functions of surface-engineered infusible cells by anchoring lipid conjugate biomaterials onto cellular membranes via hydrophobic interaction. Keywords : Ex vivo cell surface engineering, lipid conjugate, hydrophobic interaction, immune synapse Corresponding Author : Kyobum Kim (kyobum.kim@dongguk.edu)	CV
SoHyung Lee	Harvard University	Scalable Fabrication of 3D Structured Microparticles Using Induced Phase Separation	Abstract Scalable Fabrication of 3D Structured Microparticles Using Induced Phase Separation Sohyung Lee2, Dino Di Carlo*1 1UCLA, 2Harvard Medical School Scalable fabrication of hydrogel microparticles with programmable 3D geometries and spatially controlled surface chemistry remains a critical challenge for applications in single-cell biotechnology. Existing microfluidic methods face limitations in throughput and lack the capacity to localize biochemical functionality, restricting their utility for high-content screening. Here, we present a high-throughput platform combining parallelized step emulsification with temperature-induced aqueous phase separation to produce >40 million particles per hour with tunable morphologies and compartmentalized surface chemistry. By leveraging the temperature-dependent phase separation of polyethylene glycol (PEG) and gelatin, we generate monodisperse droplets that transition from miscible to phase-separated states upon cooling, enabling spatial patterning of gelatin-rich domains within photocrosslinkable microparticles. These engineered “nanovials” feature localized gelatin-functionalized cavities that promote integrin-mediated cell adhesion with >90% specificity. Single cells bound to nanovials demonstrated enhanced viability during fluorescence-activated cell sorting (FACS) compared to free-floating cells, suggesting shear-protection by the particle matrix. Furthermore, we functionalized gelatin domains to capture secreted antibodies from individual Chinese hamster ovary (CHO) cells, achieving single-cell-resolution secretion analysis without cross-talk between neighboring particles. This platform overcomes traditional complexity-throughput tradeoffs, enabling scalable production of multifunctional microparticles for applications ranging from single-cell proteomics to functional screening at unprecedented scale. Our work establishes a versatile framework for designing biomaterials that bridge cellular and microengineering paradigms, with implications for drug discovery, diagnostics, and cell therapy development. Keywords : microfluidics, single-cell study, microparticles Corresponding Author : Dino Di Carlo (dicarlo@ucla.edu)	CV
Nanshu Lu	The University of Texas at Austin	On-Scalp Printing of Personalized EEG E-Tattoos	Abstract On-Scalp Printing of Personalized EEG E-Tattoos Nanshu Lu*1 1The University of Texas at Austin Electroencephalography (EEG) is a non-invasive method essential for diagnosing neurological conditions and enabling brain-computer interfaces (BCI). Traditional EEG setups, which rely on wet conductive gels and cumbersome cables, are often labor-intensive, uncomfortable, and prone to signal degradation. Although e-tattoos—soft, skin-conformable wearable devices—have advanced various biomedical applications, they have struggled with EEG compatibility due to hair interference. Here, we report a significant advancement in EEG e-tattoo technology through the automated, on-scalp but non-contact printing of biocompatible and electrically conductive inks. Our PEDOT:PSS-based inks are specially designed for low-skin-contact-impedance electrodes and highly conductive interconnects, can be jetted through hair, dampen the scalp, and rapidly self-dry into ultrathin, skin-soft, and stretchable films. This innovation markedly enhances breathability and longevity compared to traditional gel electrodes, as well as hair compatibility and skin adhesion compared to transferred e-tattoos. Our manufacturing system employs an automated sensor layout design algorithm, customized for individual head shapes, in conjunction with a 5-axis printing robot to achieve safe and precise sensor placement. These printed e-tattoos successfully capture critical EEG markers, such as motion imagery (MI) and error-related potentials (ErrP), representing a transformative step towards personalized, comfortable, and long-term EEG monitoring. Reference 1. Cell Biomaterials 1, 100004 (2024). Keywords : additive manufacture, on-body manufacture, wearable electronics, brain-computer interface Corresponding Author : Nanshu Lu (nanshulu@utexas.edu)	CV
Dorna Esrafilzadeh	The University of New South Wales	Engineering Functional Materials for Regenerative Medicine and Biomedical Integration	Abstract Engineering Functional Materials for Regenerative Medicine and Biomedical Integration Dorna Esrafilzadeh*1 1The University of New South Wales Polymeric platforms serve as a crucial foundation in biomedical engineering due to their mechanical adaptability, chemical tunability, and induced biocompatibility. They enable the incorporation of a diverse range of biological and chemical additives, either as standalone components or in composite configurations, to enhance mechanical stability and biointerface compatibility. However, achieving an optimal balance between mechanical integrity, processability, and functional performance remains challenging. Excessive stiffness can induce a foreign body response, while inadequate structural integrity may lead to premature degradation and failure. Moreover, ensuring long-term biostability and minimizing immune response are essential for clinical translation. Recent advancements in nano and two-dimensional (2D) materials offer promising paths for enhancing the biomedical efficacy of polymeric platforms, particularly in the development of stimuli-responsive therapeutic systems. The integration of biocompatible nanostructures into polymeric matrices can significantly improve device performance in cellular stimulation, bioelectronic interfaces, and neural recording applications. Furthermore, fabrication techniques such as 3D printing allow precise integration of these materials in medical devices or the interfaces. This study focuses on the synthesis and characterization of electroactive and optically tunable nanostructured materials at the nano- and 2D scales. Their incorporation into polymeric platforms is explored for biomedical applications, including cellular regeneration and neural interfacing. By leveraging nanotechnology and advanced fabrication strategies, we aim to develop multifunctional polymeric systems that achieve enhanced biointegration, mechanical resilience, and dynamic responsiveness, ultimately advancing next-generation biomedical implants and therapeutic devices. Keywords : Polymer, Materials, biomedical engineering, device Corresponding Author : Dorna Esrafilzadeh (d.esrafilzadeh@unsw.edu.au)	CV
JUNG SEUNG LEE	Sungkyunkwan University	Extracellular and Intracellular Microenvironment Modulation for Regenerative Therapy	Abstract Extracellular and Intracellular Microenvironment Modulation for Regenerative Therapy Jung Seung Lee*1 1Sungkyunkwan University Tissue microenvironment plays crucial roles in functional homeostasis and remodelling of damaged tissues. Despite various synthetic and natural polymers have been exploited to fabricate tissue-specific or disease-specific microenvironment, there still are tremendous limitations in ultimately recapitulating structural and biochemical specificity of native tissues due to complexity. Tissue-mimicking bio-scaffolds have been highlighted as key mediators to improve regeneration efficacy by providing favourable microenvironment to cells participating directly or indirectly in the regeneration. We report tissue-derived biomaterial platforms and their engineering techniques for versatile regenerative therapeutics. In addition, not only extracellular microenvironment, but intracellular conditions are also crucial in determining cellular activities and their homeostasis. We aimed to modulate intracellular microenvironment through metabolic reprogramming of cells to induce cellular maturation and functional enhancement. In conclusion, we present technologies modulating extracellular or intracellular microenvironment to achieve enhanced regenerative therapies. Keywords : tissue microenvironment, extracellular matrix, metabolic reprogramming Corresponding Author : Jung Seung Lee (jungseunglee@skku.edu)	CV
Ha Uk Chung	Korea University	TBD		CV
Sejin Son	Inha University	Polysaccharide bioengineering technologies for therapeutic vaccine development	Abstract Polysaccharide bioengineering technologies for therapeutic vaccine development Sejin Son*1 1Inha University Microbial pathogens present “danger” signals at the site of infection and confers protective immunity by inducing proinflammatory cytokines and mobilizing leukocytes. During microbial infection, pathogen associated molecular patterns (PAMPs) of polysaccharide activate pattern recognition receptors (PRRs) expressed on innate immune cells, such as dendritic cells (DCs), leading to the production of proinflammatory cytokines. We have recently reported the development of polysaccharide mannan-based nanocapsules (Mann-NC) and also demonstrated that Mann-NC composed of mostly mannan (without any other cargo) is a potent nano-PAMP for Dectin-2 and TLR-4 activation and that intratumoral administration of Mann-NC generates robust Th17 responses in favor of antitumor effects. PAMP-PRR interaction is controlled by the geometry, nanoscale arrangement, and architecture of PAMP on Mann-NC for multivalent surface PAMP arrangement with structural flexibility for favorable PRR engagement. Here we propose polysaccharide bioengineering strategies to further increase polysaccharide’s immunogenicity by introducing chemical functional groups, nanoparticulation of native polysaccharide polymers, and their combinations. The unique and highly multidisciplinary approach to precisely modulate immune responses are widely applicable to therapeutic vaccine development for many diseases including autoimmunity, gut microbiome modulation, inflammation, and infectious diseases. Keywords : Polysaccharide, Pathogen associated molecular pattern (PAMP), Pattern recognition receptor (PRR), Therapeutic Vaccine Corresponding Author : Sejin Son (ssejin@inha.ac.kr)	CV
Will Wei Qiao	Hong Kong University	Advanced microneedle system for infectious wound healing	Abstract Advanced microneedle system for infectious wound healing Wei Qiao*1 1The University of Hong Kong Cross-kingdom polymicrobial wound infections present significant clinical challenges, including difficulties in pathogen eradication, prolonged healing times, and an elevated risk of complications. To address these issues, we have developed a dissolvable microneedle patch designed for the controlled delivery of a novel copper complex. This system enables a burst release of copper ions (Cu2+) in response to acidic biofilm environments and external light stimulation, exerting potent antimicrobial activity through oxidative stress mechanisms against polymicrobial infections. Following infection eradication, the system spontaneously tunes down Cu2+ release to resolve inflammation and promote tissue regeneration. Furthermore, we have engineered an electrically stimulated microneedle patch capable of delivering therapeutic agents into the subcutaneous layer, targeting infections that extend to deep cutaneous tissues. We demonstrated that the application of electric current not only enhances antifungal efficacy but also activates nociceptive sensory nerves, thereby eliciting protective cutaneous immunity mediated by dermal dendritic cells and γδ-T cells. Together, these microneedle-based systems offer innovative strategies for the effective management of cross-kingdom polymicrobial infections and immunomodulatory wound healing. Keywords : microneedle, skin infection, wound healing Corresponding Author : Wei Qiao (drqiao@hku.hk)	CV

10 X. Energy Harvesting Materials and Devices for Self-powered Electronics

Keynote Speakers

Sahn Nahm

Korea University

High power piezoelectric energy harvester produced using [001]-textured (K, Na)NbO3-based lead-free piezoceramics

Abstract

High power piezoelectric energy harvester produced using [001]-textured (K, Na)NbO3-based lead-free piezoceramics

Geun-Soo Lee, Byeong-Jae Min, Bu-Yeon Choi, Hyun-Ju Choi, Bumjoo Kim, and Sahn Nahm
Department of Materials Science and Engineering, Korea University, 145 Anam-ro Seongbuk-gu, Seoul 02841, Republic of Korea

The output power of piezoelectric energy harvester (PEH) is dependent on the kp and the d33×g33 values at resonance and off-resonance frequencies, respectively. The kp is proportional to d33/(εT33)1/2 and the g33 is equivalent to d33/εT33, indicating that the piezoceramics for the PEH should have a large d33 and a small εT33. The [001]-texturing can be used for developing piezoceramics for PEH because it generally increases the d33 value without the enhancement of the εT33 value. In this study, the 0.96(K0.5Na0.5)(Nb1-zSbz)O3-0.01SrZrO3-0.03(Bi0.5Ag0.5)ZrO3 [KN(N1-xSx)-SZ-BAZ] piezoceramics were textured along the [001] direction. The piezoceramic (x=0.01) showed a large kp of 0.77, which is the largest kp for KNN-related piezoceramics reported in the literature. The cantilever-type PEH manufactured using the KN(N0.99S0.01)-SZ-BAZ piezoceramic exhibited a large output power density of 7.86 mW/cm3 at resonance frequency because of its large kp. To date, this is the largest power density for PEHs manufactured utilizing lead-free piezoceramics. In addition, the PEH produced using the piezoceramic (x=0.05) exhibited the maximum output power of 4.57 μW at off-resonance frequency of 200 Hz because of its large d33 × g33. Hence, the [001]-textured KN(N1-xSx)-SZ-BAZ piezoceramics are excellent candidates for PEH, and [001]-texturing is a very efficient method for developing piezoceramics for PEH.

CV

Chengkuo Lee

National University of Singapore

TBD

Invited Speakers

Name	Affiliation	Title	Abstract	CV
Hanjun Ryu	Chung-Ang University	Wearable biomedical electronics for wound care using triboelectric nanogenerator	Abstract Wearable biomedical electronics for wound care using triboelectric nanogenerator Hanjun Ryu*1 1Chung-Ang University Chronic wounds, particularly those associated with diabetes, pose significant medical and economic challenges, necessitating effective management strategies. Electrical stimulation (ES) therapy has shown promise in accelerating wound healing by restoring disrupted endogenous electrical signals. However, conventional ES systems face limitations such as the need for secondary removal surgery and the risk of infection. Here, we present a miniaturized, wireless, battery-free, bioresorbable electrotherapy system that accelerates wound closure by guiding epithelial migration, modulating inflammation, and promoting angiogenesis. Using a mouse model, we demonstrate the system’s efficacy in enhancing the healing process while also highlighting the potential of bioresorbable materials in overcoming the limitations of traditional ES systems. This study introduces a simple yet effective chronic wound electrotherapy platform that integrates bioresorbable materials, facilitating seamless clinical translation. Keywords : Triboelectric Nanogenerator, Electrostimulation Corresponding Author : Hanjun Ryu (hanjunryu@cau.ac.kr)	CV
Sunghoon Hur	Korea Institute of Science and Technology	Probing Thermal and Energy Characteristics for Enhanced Solid-State Energy Conversion	Abstract Probing Thermal and Energy Characteristics for Enhanced Solid-State Energy Conversion sunghoon hur*1 1Korea Institute of Science and Technology The interplay of thermal, electrical, and mechanical properties in solid-state materials, particularly ferroelectrics, is critical for advancing next-generation energy conversion technologies. However, the interrelationships among these coupled properties remain largely unexplored. In this study, we developed an in situ measurement system capable of simultaneously applying an electric field and measuring both polarization and thermal conductivity in ferroelectric materials. Upon the application of an electric field, ferroelectrics undergo polarization, leading to modifications in phonon dispersion and enabling active control of thermal transport. The thermal switching behavior of a PMN-PT relaxor ferroelectric reveals that the thermal conductivity response to an electric field closely follows the polarization-electric field (PE) curve. Additionally, this setup facilitates direct investigation of the electrocaloric effect, a key mechanism in solid-state cooling, demonstrating its potential for high-efficiency thermal management and cooling applications. These findings underscore the promise of ferroelectrics for small-scale thermal regulation in energy conversion technologies, offering a pathway toward innovative and sustainable cooling solutions. Keywords : Electrocaloric, Ferroelectrics, Thermal Conductivity, Electric Field, Cooling Corresponding Author : sunghoon hur (hur@kist.re.kr)	CV
Jun Chen	UCLA	Discovering Magnetoelasticity in Soft Matter for Bioelectronics	Abstract Discovering Magnetoelasticity in Soft Matter for Bioelectronics Jun Chen*1 1Department of Bioengineering, University of California, Los Angeles The magnetoelastic effect, also named as Villari effect and discovered in 1865 by Italian experimental physicist Emilio Villari, is the variation of the magnetic field of a material under mechanical stress. This effect is usually observed in rigid metal and metal alloys with an externally applied magnetic field and has been ignored in the field of soft bioelectronics for the following three reasons: the magnetization variation in the biomechanical stress range is limited; the requirement of the external magnetic field induces structural complexity and bulky structure, and there exists a gigantic mismatch of mechanical modulus up to six orders of magnitude difference between the rigid magnetoelastic materials and the soft human tissues. In 2021, we discovered the giant magnetoelastic effect in a soft solid polymer system, later in a liquid permanent fluidic magnet, which paves a fundamentally new way to build up intrinsically waterproof and biocompatible soft bioelectronics for diagnostics, therapeutics, and energy applications. Our group at UCLA is currently pioneering this research effort of harnessing giant magnetoelastic effect in soft systems for personalized healthcare and sustainable energy. Keywords : Magnetoelastic Effect; Magnetoelastic Generators; Self-Powered Sensors; Corresponding Author : Jun Chen (jun.chen@ucla.edu)	CV
Hong Joon Yoon	Gachon University	Ultrasound-driven triboelectrification for powering electronics	Abstract Ultrasound-driven triboelectrification for powering electronics Hong-Joon Yoon*1 1Gachon University Ultrasound-based mechanical energy harvesting materials and thereof devices emerge as a promising technology for powering implantable electronic devices within the human body. Although this approach takes advantage of ultrasound's noninvasive nature, the compact design inherent in frictional electricity-generating components, and the biocompatibility of materials engaged in friction, the behavior of frictional materials under ultrasound necessitates a systematic and controllable design strategies. Here, we present the development of an ultrasound energy harvesting device engineered for long-term stability. Our results found that the incidence and reflection characteristics of ultrasound interestingly vary upon pairs of materials exhibiting disparate moduli in the ultrasound environment. We not only experimentally but also theoretically establish that a pronounced difference in modulus values between materials facilitates the generation of high-amplitude oscillations. Importantly, we validate that the manifestation of oscillations during ultrasound propagation is governed by the high and low modulus boundaries encountered by the material. This design strategy may benefit long-term performance of the ultrasound-based energy harvesting device. We, through this design strategy, experimentally validated that the ultrasound-based energy harvesting device that has the potential for long-term stability (>6 weeks) and continuous power generation. Keywords : Ultrasound, Triboelectric Nanogenerator, Triboelectrification, Stability Corresponding Author : Hong-Joon Yoon (yoonhj1222@gachon.ac.kr)	CV
Sang Hyo Kweon	Kobe University	Sol-gel Derived Epitaxial Pb(Zr,Ti)O3 Thin Films on Si substrate: Enhancement of Piezoelectricity through Compositional and Structural Modification	Abstract Sol-gel Derived Epitaxial Pb(Zr,Ti)O3 Thin Films on Si substrate: Enhancement of Piezoelectricity through Compositional and Structural Modification Sang Hyo Kweon1, Isaku Kanno*1 1Kobe University Epitaxial Pb(Zr,Ti)O3 (PZT) thin films with Zr/Ti ratio of 45/55, 52/48 and 60/40 (PZT(45/55), PZT(52/48) and PZT(60/40), respectively) were prepared on Si(001) substrates by a sol-gel method. We adopted the unimorph cantilever method to characterize the dependence of converse transverse piezoelectric coefficient (\|e31,f\|) on applied voltages. It was revealed that \|e31,f\| values of the PZT(45/55) and the PZT(52/48) were 9.7-11.5 C/m2 and 11.2-12.5 C/m2, respectively, showing a strong relation with applied voltage. In contrast, \|e31,f\| of the PZT(60/40) film was 11.7-12.3 C/m2 with a small voltage dependence. In-situ reciprocal space mapping (RSM) images were taken under the existence of DC biases with a synchrotron radiation X-ray diffraction (SR-XRD) to correlate the change of crystal structures with respect to the behavior of \|e31,f\|. Moreover, hetero-layered epitaxial PZT (HL-PZT) thin films were fabricated by stacking PZT thin films with different compositions. It was found that crystal structures and compositional distribution along the thickness direction of the films varied significantly depending on the stacking sequence. In particular, the HL-PZT, with the PZT(45/55) as the first layer alternately stacked with the PZT(60/40), exhibited the highest \|e31,f\| of 15.9 C/m2. The SR-XRD measurements showed that lattice elongation due to intrinsic effect was more pronounced in HL-PZT compared to single-phase PZT thin films. This result suggests that the piezoelectric properties of sol-gel derived epitaxial PZT thin films can be enhanced by constructing a heterostructure and optimizing both the composition and stacking sequence of the PZT layers. Keywords : sol-gel, epitaxial growth, PZT, Si substrates, transverse piezoelectricity Corresponding Author : Isaku Kanno (kanno@mech.kobe-u.ac.jp)	CV
Ji-Soo Jang	Korea Institute of Science and Technology	Power generation from asymmetric greenhouse gas capture	Abstract Power generation from asymmetric greenhouse gas capture Ji-Soo Jang*1 1Korea Institute of Science and Technology The demand for reducing greenhouse gas (GHG) emissions to address climate change is intensifying, and international efforts to curb emissions of significant greenhouse gases are currently underway. Specifically, CO2 is considered a major driver of global warming as a result of rising fossil fuel consumption and environmental destruction, while emissions of NOx from vehicle exhaust and agricultural practices are also acknowledged as important contributing factors. Despite ongoing efforts to develop carbon capture, utilization, and storage (CCUS) technologies for the reduction of greenhouse gas emissions and increased re-utilization efficiency, significant limitations persist due to challenges in the selective capture of greenhouse gases and the essential requirement for catalysts in re-utilization processes. Consequently, new strategies are required to selectively capture greenhouse gases while minimizing energy consumption and facilitating their effective re-utilization. Keywords : Gas capture, energy harvesting, Green energy Corresponding Author : Ji-Soo Jang (wkdwltn92@kist.re.kr)	CV
Kyungwho Choi	SungKyunKwan University	Advanced Functional Composites for Self-Powered Sensors	Abstract Advanced Functional Composites for Self-Powered Sensors Kyungwho Choi*1 1Sungkyunkwan University Inorganic semiconductor materials have been intensively studied for thermoelectric energy conversion, but they typically contain heavy, brittle, toxic, expensive elements and require complicated or/and costly manufacturing processes. These disadvantages have been impeded wide use of thermoelectric systems despite their compactness, silence/robustness due to no-moving parts, and versatility in energy harvesting and refrigeration. In this presentation, carbon nanotube-based nanocomposites are expected to offer a solution for the drawbacks. Low thermal conductivity of typical organic materials is best suited to thermoelectrics, but their poor electrical properties accompanied by the strong correlation between thermoelectric properties have prevented them as feasible candidates. For instance, when electrical conductivity is raised to a value close to semiconductors, thermopower generally becomes extremely small. However, this approach uses electrically connected, but thermally disconnected junctions, making thermoelectric transport properties relative independent. In order to build a leg-type structure, metal nanoparticles and/or organic molecules were introduced to the CNT surfaces. Due to the difference in electronic status of the two adjacent materials, it was possible to manipulate the electrical properties (p- or n-type) of the composites by electron migration. From those flexible organic composites, p- and n-type module was developed for thermoelectric energy harvesting. With optimized device design to maximally utilize temperature gradients, an electrochromic glucose sensor was successfully operated without batteries or external power supplies, demonstrating self-powering capability. While this fundamental study provides a method of tailoring electronic transport properties, this device-level integration shows the feasibility of harvesting electrical energy by attaching the device to even curved surfaces like human bodies. Keywords : Thermoelectrics, Energy harvesting, Carbon nanotubes, Flexible conductor, Seebeck coefficient Corresponding Author : Kyungwho Choi (kw.choi@skku.edu)	CV

11 XI. Materials for Environmental Science

Keynote Speakers

Jae Sang Lee

Korea University

Exploring the major degradative pathway and catalytic center during heterogeneous persulfate activation

Abstract

Exploring the major degradative pathway and catalytic center during heterogeneous persulfate activation

Jaesang Lee*1

1Korea University

Heterogeneous catalysis performs sulfate radical production during persulfate activation in the same way as low-valent transition metals generate oxidizing radicals from inorganic peroxides through the heterolytic cleavage of a peroxide bond in the Haber-Weiss reaction mechanism. Alternatively, selected metallic and carbonaceous materials promote the reactivity of persulfate toward organics without radical formation. Non-radical degradative pathways include oxidation by high-valent metal species, singlet oxygenation, and mediated electron transfer. Sulfate radical identified as the dominating oxidant in the radical-based persulfate activation exhibits the insignificant sensitivity of oxidizing capacity to the substrate type whereas non-radical persulfate activation typically enables the selective oxidation of electron-rich organics (e.g., phenols). Accordingly, the preceding studies on the technical benefits of radical and non-radical persulfate activation processes imply a trade-off between the treatability of a broad range of organic pollutants and minimal kinetic interference in the presence of background water matrix. In this presentation, we provide multiple instances of radical and non-radical organic degradation during heterogeneous persulfate activation via various redox catalysis, introduce the experimental approaches to distinguish the reaction pathways based on their distinct characteristics, and demonstrate the possibility of switching the primary degradative routes (or catalytic sites) according to the structural properties and chemical compositions of catalysts, operating conditions, and the type of persulfate precursor.

Keywords : Heterogeneous catalysis; persulfate activation; radical and non-radical oxidation, water treatment; transition in the major degradative pathway

Corresponding Author : Jaesang Lee (lee39@korea.ac.kr)

CV

Gopalakrishnan Kumar

University of Stavanger

Functional biodegradable polymers from lignocellulose biomass: Production and stabilisation

Abstract

Functional biodegradable polymers from lignocellulose biomass: Production and stabilisation

Gopalakrishnan KUMAR*1, Bibi Nausheen Jaffeur3, Joonhong Park2

1University of Stavanger, 2School of Civil and Environmental Engineering, Yonsei University, Seoul 03722, Republic of Korea, 3Department of Chemical and Environmental Engineering, Faculty of Engineering, University of Mauritius, Réduit 80837, Mauritius

Poly(3-hydroxybutyrate) (PHB) was produced from Furcraea foetida using Cupriavidus necator and investigated for improved mechanical performance, thermal stability, and flexibility through composite blending with microcrystalline cellulose (MCC), polylactic acid (PLA), lignin, and polyethylene glycol (PEG). PHB, known for its high crystallinity, good mechanical strength, and biocompatibility, exhibits brittleness and thermal degradation, limiting its processability. Tensile strength increased from 27.16 MPa for pure PHB to 47.77 MPa with 20% PLA, 54.91 MPa with 50% MCC, and 60.77 MPa with 50% PLA. Elongation at break improved from 2.15% for pure PHB to 4.34% with 50% PEG, enhancing flexibility. Thermogravimetric analysis showed improved thermal stability, with PHB-MCC and PHB-lignin blends delaying degradation onset to 294.8 °C, compared to 275 °C for pure PHB. PHB-lignin blends exhibited mass loss of 70.41% for 40% lignin and 95.24% for 50% lignin over 180 days, reflecting the influence of lignin on biodegradation. PHB-PLA blends-maintained degradation rates of 85–94%, ensuring controlled biodegradability. SEM analysis confirmed uniform dispersion of MCC and PLA, reducing microcracks and improving mechanical properties. PHB-MCC composites provided high stiffness and thermal resistance for structural applications, while PHB-PEG blends improved flexibility for biomedical uses. PHB-PLA blends balanced strength and biodegradability, making them suitable for packaging and medical devices. The enhanced properties of these composites expand the applicability of PHB for high-performance biodegradable materials, contributing to the development of sustainable alternatives to petroleum-based plastics.

Keywords : PHA, PHA-blends, Sustainable materials, lignin, biodegradable Polymers

Corresponding Author : Gopalakrishnan KUMAR (gopalakrishnanchml@gmail.com)

Invited Speakers

Name	Affiliation	Title	Abstract	CV
Changha Lee	Seoul National University	Copper-Based Redox Systems for Microbial Inactivation	Abstract Copper-Based Redox Systems for Microbial Inactivation Changha Lee*1 1Seoul National University The disinfection of environmental media contaminated with pathogenic microorganisms is essential to protect public health from diseases. To date, various disinfection methods have been developed in response to the threat of different species of pathogens. Among them, chemical disinfection is a strong and rapid tool capable of inactivating a broad spectrum of microorganisms in water and other media. For water disinfection, chemical oxidants such as chlorine, chlorine dioxide, and ozone have been extensively studied and used in water treatment plants. These oxidants are known to damage cell membranes, nucleic acids, mitochondria, as well as other cellular components of microorganisms. However, these conventional disinfectants can produce harmful disinfection by-products through reactions with natural or anthropogenic organic substances in water. Copper is a well-known microbicide that has been widely used to control microorganisms. Copper ions bind to reactive sites on proteins and DNA in microbial cells, leading to dysfunctions in these biomolecules. Cuprous ion (Cu(I)) is recognized to be more cytotoxic than cupric ion (Cu(II)). The microbicidal effect of exogenous Cu(II) has been suggested to be attributed to the toxicity of Cu(I) reductively generated in the intracellular region. The combination of Cu(II) with different redox systems (oxidants or reductants, or their production systems) generates multiple species that exhibit different microbicidal mechanisms towards bacteria and viruses. In particular, cupryl ion (Cu(III)), a high-valent copper ion, was found to be a selective virucide. Here, we present different microbicidal systems based on redox reactions of copper. In these systems, the mechanisms through which microorganisms are inactivated are discussed, with a focus on the roles of redox species of copper. Keywords : Disinfection, Copper, Cupryl ion, Redox reactions Corresponding Author : Changha Lee (leechangha@snu.ac.kr)	CV
Chanhee Boo	KAIST	Oxidation-Resistant Polysulfonate-ester (PSE) Nanofiltration Membranes for Recycling of Waste Solutions from Semiconductor Industry	Abstract Oxidation-Resistant Polysulfonate-ester (PSE) Nanofiltration Membranes for Recycling of Waste Solutions from Semiconductor Industry Chanhee Boo*1, Yejin Han1 1Korea Advanced Institute of Science and Technology Waste solutions from the semiconductor industry contain high levels of oxidants such as hydrogen peroxide used for wafer surface etching and cleaning. Conventional polyamide (PA) nanofiltration (NF) membranes are widely employed for industrial wastewater treatment due to their superior separation performance. However, polyamide NF membranes are susceptible to oxidative degradation induced by hydrogen peroxide, and thus, their uses in the recycling of semiconductor waste solutions are limited. In this study, we report a novel molecular-level design to fabricate polysulfonate-ester (PSE) NF membranes with enhanced oxidation-resistance via interfacial polymerization (IP) of phenoxide and sulfonyl chloride monomers, followed by end-capping treatment. Three different types of end-capping agents were used to convert residual hydroxyl groups in the PSE matrix into chemically-inert terminal groups. We found that end-capping treatment imparts the chemical stability and steric hindrance to the polymer structure, playing a key role to mitigate membrane degradation by oxidative attack. Performance stability of the PSE NF membranes was evaluated in terms of water permeability and salt (Na2SO4) rejection for 7 days under exposure to 1 wt% hydrogen peroxide. Our results demonstrate that the PSE NF membranes end-capped with sulfonyl terminal group have a stronger resistance toward oxidative attack by hydrogen peroxide than PA NF membranes, offering a promising solution to address the challenges of recovering valuable oxidizing agents from harsh semiconductor waste solutions. Keywords : Nanofiltration, Oxidation, Semiconductor Waste Solution Corresponding Author : Chanhee Boo (chanhee.boo@kaist.ac.kr)	CV
Seunghyun Weon	Korea University	Carbon Cocatalysts for Photocatalytic Air Purification: Instability and Carbon Neutrality Challenges	Abstract Carbon Cocatalysts for Photocatalytic Air Purification: Instability and Carbon Neutrality Challenges Seunghyun Weon*1 1Korea University Photocatalytic air purification offers significant advantages over adsorption filtration by efficiently degrading gaseous pollutants through reactive oxygen species (ROS) generation. Among various photocatalyst designs, those incorporating carbon nanomaterials as cocatalysts are considered highly promising due to their perceived environmental and economic benefits compared to noble metals. However, our study indicates a critical drawback in these systems, particularly under atmospheric conditions with low reactant densities. Increased ROS generation leads to the degradation of the carbon-cocatalyst C-C network, diminishing the photocatalytic efficiency. This continuous degradation process not only reduces effectiveness but also results in the unintended mineralization of carbon cocatalysts into CO2, thereby contributing to Scope 3 carbon emissions. Through detailed examinations of various carbon cocatalysts loaded onto TiO2, we confirmed the mechanisms of this self-destruction, the associated efficiency losses, and the resultant CO2 emissions. An economic analysis comparing these carbon-based systems with noble metal alternatives highlights significant considerations regarding material costs, accumulated depreciation, and CO2 emission taxes. The findings suggest that the potential environmental drawbacks of carbon cocatalysts might negate their benefits in photocatalytic air purification, necessitating a paradigm shift from a sole focus on material costs to a broader consideration of carbon neutrality scenarios in future photocatalyst development. Keywords : Photocatalysts, Cocatalyst, Carbon nanomaterials, Charge separation Corresponding Author : Seunghyun Weon (s_weon@korea.ac.kr)	CV
Kangwoo Cho	POSTECH	Electrochemical Water Oxidation to Ozone for Advanced Water Treatment	Abstract Electrochemical Water Oxidation to Ozone for Advanced Water Treatment Kangwoo Cho*1 1Pohang university of science and technology Aqueous ozone is a strong oxidant to be widely deployed in advanced oxidation processes for water treatment. Electrochemical six-electron water oxidation reaction (6e-WOR) can be a lower-energy alternative to the existing corona discharge for ozone generation. Ni-Sb-SnO2 (NSS) has been a representative ozone evolution reaction (OZER) electrocatalyst whose practical use is yet limited due to low efficiency. In particular, it is challenging to foster selective OZER in competition with thermodynamically favored oxygen evolution reaction (OER). This presentation shows our recent achievements to intensify the OZER based water treatment. First, the mechanism of OZER was revisited by experimental and theoretical approaches. Second, the OZER selectivity could be tuned by overcoating various metal oxides on NSS. The heterojunction NSS/SiOx anode with a proper surface charge density showed 2.7-fold increase in current efficiency. Third, the OZER anode was combined with UV or H2O2 generating cathode to degrade recalcitrant pollutants with •OH in terms of E-UV/O3 or E-peroxone process. Lastly, the NSS/SiOx anode was integrated into a membrane electrode assembly (MEA) for drinking water treatment with negligible electrical conductivity. The findings of this study would broaden the applications of electrochemical advanced oxidation processes. Keywords : Electrocatalysts; Water; Ozone; Advanced Oxidation Process Corresponding Author : Kangwoo Cho (kwcho1982@postech.ac.kr)	CV
Hongsik Yoon	KOREA INSTITUTE OF MACHINERY & MATERIALS	Hybrid Capacitive Deionization for Wastewater Treatment from Spent Battery	Abstract Hybrid Capacitive Deionization for Wastewater Treatment from Spent Battery Hongsik Yoon*1 1Korea Institute of Machinery & Materials With the increasing demand for lithium-ion batteries, the generation of spent batteries and associated wastewater has surged, necessitating efficient and selective treatment technologies. Conventional wastewater treatment methods, including precipitation, adsorption, and membrane filtration, face challenges such as high chemical consumption, low selectivity, and sludge production. In this study, we propose a novel hybrid capacitive deionization (HCDI) system incorporating Ag-coated activated carbon (AC) electrodes for the selective removal of lithium (Li) and other metal ions from spent battery wastewater. The Ag-coated AC electrodes enhance electrochemical adsorption through the Ag/AgCl redox reaction, improving ion selectivity and deionization capacity. Compared to conventional membrane capacitive deionization (MCDI), the developed HCDI system demonstrated a 32% increase in lithium uptake, with a selectivity coefficient for Li+ over Na+ reaching 171. Additionally, the introduction of a stop-flow operation further improved Li+ selectivity, optimizing ion recovery efficiency. The energy consumption of the HCDI system was significantly lower than traditional electrochemical processes, highlighting its potential for sustainable wastewater treatment. Furthermore, the system was also applied for nickel (Ni) treatment, achieving a 66% higher deionization capacity than MCDI, demonstrating its versatility for various heavy metal removal applications. This study provides valuable insights into the development of energy-efficient and high-selectivity electrochemical deionization systems for the recycling and purification of wastewater from spent batteries. Keywords : Spent battery, Capacitive deionization, Silver, Nickel, Lithium Corresponding Author : Hongsik Yoon (yoonhs@kimm.re.kr)	CV
Sungjun Bae	Konkuk University	Biochar materials for environmental applications	Abstract Biochar materials for environmental applications Sungjun Bae*1 1Konkuk University Biochar has emerged as a promising material for environmental remediation, particularly in the removal of heavy metals and organic contaminants from aqueous environments. This study explores the potential of biochar in removing hexavalent chromium (Cr(VI)), copper (Cu), and in facilitating ketoprofen photodegradation. Biochar, derived from various biomass sources, exhibits a high surface area, abundant functional groups, and strong adsorption capabilities, making it an effective adsorbent for water purification. These findings highlight biochar’s potential as a sustainable and cost-effective material for mitigating various environmental pollutants. Future research should focus on optimizing biochar properties through modifications, exploring synergistic effects with other remediation techniques, and scaling up applications for real-world wastewater treatment systems. Keywords : biochar, adsorption, oxidation, reduction Corresponding Author : Sungjun Bae (bsj1003@konkuk.ac.kr)	CV
Moon Son	KIST	Battery Electrodes for Brackish Water Desalination	Abstract Battery Electrodes for Brackish Water Desalination Moon Son*1 1Korea Institute of Science and Technology; University of Science and Technology Desalination technology using electrochemical reactions has progressed by leaps and bounds since the invention of the capacitive deionization (CDI) process using carbon electrodes in the 1960s. However, conventional CDI technology often suffers from limited salt adsorption capacity and low thermodynamic energy efficiency because it relies solely on the formation of an electrostatic double layer on the electrode surface. To overcome this limitation, battery electrodes capable of intercalating anions or cations have been later introduced. These battery electrode-based desalination technologies are often named battery electrode deionization (BDI) and are classified into symmetric (using anode/cathode of the same end) or asymmetric configurations depending on their structure. In this presentation, we will introduce the BDI technology utilizing cation intercalating electrodes (Prussian blue analogues, molybdenum disulfide, etc.) and discuss its advantages/disadvantages and future development directions. Since the configuration, including the location of the ion exchange membrane, has a significant influence on the desalination performance, the variations and pertinent mechanisms of water desalination performance depending on the configuration will then be discussed. Keywords : Battery electrodes, Electrochemical cells, Water Desalination, Capacitive Deionization Corresponding Author : Moon Son (moonson@kist.re.kr)	CV
Byeongcheul Moon	KIST	Metallic Electrodes for Microbial Electrosynthesis: Risk and Opportunities	Abstract Metallic Electrodes for Microbial Electrosynthesis: Risk and Opportunities Byeongcheul Moon*1 1Korea Institute of Science and Technology Microbial electrosynthesis (MES) presents a promising approach to converting anthropogenic CO2 into value-added chemicals, supporting carbon neutrality and sustainable biomanufacturing powered by renewable electricity. However, optimizing electrode performance, electron transfer efficiency, and scalability remains challenging. This talk explores the risks and opportunities associated with the use of metallic electrodes in MES. Key risks include metal ion leaching, biofouling, and the generation of undesirable byproducts, all of which can inhibit microbial growth and reduce MES productivity. These limitations restrict the full potential of metallic electrodes in MES systems. Conversely, metallic electrodes offer significant opportunities due to their tunability, especially when engineered with nanostructures or surface modifications. In this study, we developed a self-detoxifying metallic electrode that suppresses the generation of hydrogen peroxide (H2O2), a reactive oxygen species known for its cytotoxicity and harmful effects on microbial growth. This was achieved by engineering the electrode surface with relatively low-toxic elements to enhance both corrosion resistance and minimize H2O2 production. This approach led to a 50% improvement in MES performance by replacing carbon electrode with metallic electrodes. Our findings present a promising strategy for designing metallic electrodes for bioelectrochemical systems, overcoming key limitations in their application to MES. This study provides valuable insights into addressing critical challenges of metallic electrodes and highlights opportunities for enhancing their performance in bioelectrochemical applications. Keywords : electrochemistry, microbial electrosynthesis, hydrogen evolution, biocompatible, CO2 conversion Corresponding Author : Byeongcheul Moon (bcmoon@kist.re.kr)	CV
Woochul Song	POSTECH	Bioinspired channel-based membranes: a new membrane platform for aqueous separations	Abstract Bioinspired channel-based membranes: a new membrane platform for aqueous separations Woochul Song*1 1POSTECH Membrane based water separations have been an attractive technology to help address global water challenges. However, overcoming current membranes’ separation limits has not been successful compared to overall advances of the other water treatment technologies during the last decades. In this seminar, we will discuss bioinspired channel-based membranes as a next-generation membrane platform to help resolve this challenge. First, our first-ever full synthetic channel-based membranes will be introduced that translated the structure-to-function relations of biological membranes in synthetic membrane models. Then, a new type of synthetic water channel will be presented as a key element of bioinspired membranes to enable fast and selective water transport for desalination applications. Overall, these channel-based membranes showed intrinsic permselectivity that exceeds the current polymeric membranes’ tradeoffs by orders of magnitudes, highlighting their potential as a new membrane platform for sustainable water separations and purification. Keywords : Biomimetic Membranes Corresponding Author : Woochul Song (woochulsong@postech.ac.kr)	CV
Jonghun Lim	Sungshin Women's University	Copper Phosphide as an Environmental Catalyst	Abstract Copper Phosphide as an Environmental Catalyst Jonghun Lim*1 1Sungshin Women's University Copper phosphide has been extensively studied for energy applications due to its high electrical conductivity and rapid redox kinetics. However, its potential as an environmental catalyst remains largely underexplored, with only a limited number of studies reported. One of the key challenges limiting its practical application is its reactivity being confined to acidic conditions, where it suffers from severe instability due to ion dissolution. To overcome these limitations, we have developed a series of strategies aimed at enhancing the stability and broadening the applicability of copper phosphide in environmental catalysis. In this presentation, I will introduce three distinct approaches. First, I will discuss the selective degradation of pollutants through the generation of singlet oxygen under neutral conditions, utilizing copper phosphide as a photocatalyst. Second, I will highlight its role as a peroxymonosulfate (PMS) activator, enabling stable pollutant degradation under neutral and alkaline conditions. Finally, I will present a photoelectrochemical system in which copper phosphide functions as a cathode, facilitating the generation of hydroxyl radicals not only at the blue TiO2 nanotube anode but also at the copper phosphide cathode, thereby significantly enhancing pollutant degradation efficiency. These strategies collectively expand the utility of copper phosphide as a robust and versatile environmental catalyst, offering new pathways for sustainable and efficient pollutant remediation. Keywords : Copper phosphide, Environmental catalyst, Advanced oxidation processes, Water treatment Corresponding Author : Jonghun Lim (jlim@sungshin.ac.kr)	CV
Karthikeyan Sekar	SRM Institute of Science and Technology	Design strategy: well-defined Cu2O-based materials for antibiotic removal from water and H2 generation	Abstract Design strategy: well-defined Cu2O-based materials for antibiotic removal from water and H2 generation Karthikeyan Sekar1, Hyoung-il Kim*1 1Yonsei University Abstract: Solar photocatalytic processes offer a promising approach to environmental energy and remediation; nevertheless, their application demands advancements in visible light harvesting and conversion, a particular focus on low-cost, earth-abundant materials. Semiconducting copper oxides show promise as visible light photocatalysts for solar fuels production and water depollution. In this talk, I'll speak about the Cu2O based materials design strategy (i.e. mild, hydrothermal, template and template-free synthesis) of core-shell, hierarchical, cubic, and well-defined structures/sizes for visible light photocatalytic energy and environmental applications. Short Bio: Dr. Karthikeyan Sekar is currently working as a Brian Pool Fellow (Yonsei University)/Research Assistant Professor at SRM Institute of Science and Technology, India, and as a visiting faculty member at the University of Edinburgh, Scotland, UK, and University of Cologne, Germany. He is also a JSPS Invitational Fellow at Kyushu University, Japan. Before joining SRMIST, he worked as a special researcher at the University of Tokyo. He received the prestigious Royal Society Newton International Alumni Grant, the Japan Society for the Promotion of Science Fellowship at Kyushu University, Japan (2018-2020), and the Royal Society Newton International Fellowship at Aston University, UK (2016-2018). He was awarded Fellowship of the Higher Education Academy, United Kingdom, in 2018. He is also an International Academic Partner of the Africa Centres of Excellence Project. His research interests focus on the development of biomass-derived carbon-based materials used as catalysts for energy and environmental remediation. Dr. Sekar has published more than 120 research articles in high-impact journals (e.g., Advanced Energy Materials, Applied Catalysis B: Environmental, Journal of Materials Chemistry A, Chemical Communications, ChemSusChem, etc.) with a citation count of 6500 and an h-index of 38. He also holds four patents (including one international), many of which have impacted industries in India and abroad. Keywords : Cu2O, Nanomaterials Design, Surface Chemistry, Environmental, Energy. Corresponding Author : Hyoung-il Kim (hi.kim@yonsei.ac.kr)	CV

12 XII. Advanced Materials and Technologies for Next-Generation Solar Cells

Keynote Speakers

Oki Gunawan

IBM Research

Electronic Trap Detection with Carrier-Resolved Photo-Hall Effect: A New Advance in the 145-Year-Old Hall Effect and its Application in Perovskites

Abstract

Electronic Trap Detection with Carrier-Resolved Photo-Hall Effect: A New Advance in the 145-Year-Old Hall Effect and its Application in Perovskites

Oki Gunawan*2, Byungha Shin1, Chaeyoun Kim1, Bonfilio Nainggolan3

1KAIST, 2IBM Research, 3Arizona State University

We present an exciting discovery of a new equation and technique to detect semiconductor traps based on photo-Hall effect. Defects or traps in semiconductors are very important as they directly impact the performance of various semiconductor devices. We show that by analyzing “photo-Hall conductivity” versus electrical conductivity with varying light intensities and temperatures, we uncover an astonishingly simple hyperbola equation that reveals detailed charge transport and trap occupation. We demonstrated this technique in high-performance perovskite photovoltaics films and silicon. This technique significantly expands Hall effect-based measurements by integrating electric, magnetic, photon, and phonon excitations into a single framework and enables unparalleled extraction of charge carrier and trap properties in semiconductors.

Keywords : perovskite, photo-Hall effect

Corresponding Author : Oki Gunawan (oki.gunawan@gmail.com)

CV

Jin Young Kim

Seoul National University

Perovskite-based tandems: Perovskite/Si 2J and beyond

Abstract

Perovskite-based tandems: Perovskite/Si 2J and beyond

Jin Young Kim*1

1Seoul National University

Perovskite/Si double-junction (2J) tandem solar cells are attracting interest due to their rapidly increasing efficiency. Their certified record efficiency (33.9%) has surpassed the theoretical limit efficiency of single-junction (1J) solar cells. In this presentation, recent research progresses in the high-efficiency and stable perovskite/Si 2J tandem researches done in our lab will be briefly introduced,[1-3] and novel approaches to develop perovskite tandems beyond the perovskite/Si 2J tandems with record-high efficiencies, such as the perovskite/perovskite/Si triple-junction (3J) tandems,[3] perovskite/CZTSSe 2J tandems,[4] and perovskite/CIGS 2J tandems will be discussed.

References
[1] Park et al., Joule, 3, 807 (2019).
[2] Kim et al., Science, 368, 155 (2020).
[3] Ji et al., Joule, 6, 2390 (2022).
[4] Choi et al., ACS Energy Lett., 8, 3141 (2023).
[5] Hwang et al., Energy Environ. Mater., 7, e12489 (2024).

Keywords : perovskite, tandem

Corresponding Author : Jin Young Kim (jykim.mse@snu.ac.kr)

CV

Invited Speakers

Name	Affiliation	Title	Abstract	CV
Byungha Shin	KAIST	Efficient and stable tandem solar cells enabled by wide-bandgap perovskites prepared with anion-engineered 2D additives	Abstract Efficient and stable tandem solar cells enabled by wide-bandgap perovskites prepared with anion-engineered 2D additives Byungha Shin*1 1KAIST Perovskite photovoltaic technology has advanced substantially, with the present record efficiency for single-junction devices reaching > 25%. One of the most promising strategies for commercializing these devices is to apply a perovskite top cell in tandem with a Si bottom cell to reach ultrahigh efficiency beyond the Shockley-Queisser limit for single-junction devices. The ideal band gap for the tandem configuration is ~1.67 to 1.75 eV for the top cell and 1.12 eV for the bottom cell. The band gap of perovskites can be tuned by (partial) replacement of iodine anions with bromine or chlorine. However, the replacement of I with Br by more than 20%, which is necessary to enlarge the band gap to ~1.7 eV, leads to stability issues under illumination through phase separation that forms I-rich and Br-rich structures. One approach to stabilize the perovskite is to create a two-dimensional (2D) phase in which sheets of [PbX6]2- octahedra are separated by an excess number of long-chain (or aromatic) molecules that act as a passivation agent. Common long-chain or aromatic molecule-based 2D additives include n- butylammonium iodide (n-BAI) and phenethylammonium iodide (PEAI). Most of the recent studies have focused on the cation components of the 2D additives rather than focusing on the anions. We developed a 2D-3D mixed wide band gap (1.68 eV) perovskite using a mixture of thiocyanate (SCN) with the more conventional choice, iodine. Through a careful application of atomic resolution transmission electron microscopy, we demonstrated that electrical and charge transport properties as well as the physical location of 2D passivation layers can be controlled with anion engineering of the 2D additives. Moreover, we can use this approach to extend light stability and to improve device performance. For a perovskite device, we achieved a PCE of 20.7% that retained > 80% of its initial efficiency after 1000 hours of continuous illumination in working conditions. For monolithic 2T perovskite/Si tandem solar cells, the top-performing 2T tandem device achieved a PCE of 26.7%. In the case of monolithic perovskite/CIGS tandem solar cells, we utilized a narrow bandgap CIGS with single band grading, which proved to be more advantageous than the traditional double-graded CIGS typically optimized for single-junction CIGS solar cells, resulting in an efficiency of 25.1%. Keywords : perovskite, tandem, Silicon, CIGS Corresponding Author : Byungha Shin (byungha@kaist.ac.kr)	CV
Jae Sung Yun	University of Surrey	Challenges and Prospects of Halide Perovskite Solar Cells for Space Applications	Abstract Challenges and Prospects of Halide Perovskite Solar Cells for Space Applications Jae Sung Yun*1 1School of Computer Science and Electronic Engineering, Advanced Technology Insitute, University of Surrey University Halide perovskite solar cells (PSCs) have emerged as a promising candidate for space photovoltaics due to their high power-to-weight ratio, tunable bandgap, and potential for low-cost manufacturing. However, their deployment in space necessitates thorough evaluation under harsh environmental conditions, including high-energy particle radiation and extreme thermal cycling. This study presents recent findings from proton radiation exposure and thermal shock tests on halide PSCs, providing critical insights into their viability for space applications. Proton radiation tests were conducted to assess the impact of high-energy particles on the structural and electronic properties of perovskite absorbers. While PSCs exhibit promising radiation tolerance, prolonged exposure can introduce deep-level defects that degrade performance. Strategies for mitigating radiation-induced damage, including passivation techniques and defect-tolerant perovskite compositions, are discussed. Thermal shock tests, simulating rapid temperature fluctuations from –85°C to 85°C, reveal critical stability challenges. Phase-stable FAPbI₃ perovskites demonstrate high resilience under these conditions, suggesting their potential for space applications. However, thermal stress at material interfaces remains a key issue. Optimizing the bulk perovskite layer and developing robust interlayer engineering approaches are essential to enhance mechanical integrity and long-term performance in low-Earth orbit and deep-space missions. These findings highlight key degradation mechanisms and inform strategies to improve the space durability of perovskite photovoltaics. Future research should focus on radiation-hardened perovskite formulations, thermally stable interfacial materials, and advanced encapsulation strategies to establish PSCs as a viable alternative for space-based solar power and satellite applications. Keywords : solar cells, halide perovskites, space applications, satellite, radiation Corresponding Author : Jae Sung Yun (j.yun@surrey.ac.uk)	CV
Yen-Hung Lin	HKUST	Towards Viable Perovskite Photovoltaic Technologies	Abstract Towards Viable Perovskite Photovoltaic Technologies Yen-Hung Lin*1 1The Hong Kong University of Science and Technology Since their successful demonstration in a solid-state configuration in 2012 by Park, Snaith, and coworkers, halide perovskite solar cells have rapidly advanced as a promising photovoltaic technology. Their potential for low-cost, high-efficiency energy generation arises from unique material properties such as tunable bandgaps, strong light absorption, and facile processing routes. Yet, these same advantages can be a double-edged sword: the low thermal budgets of perovskites render them vulnerable to moisture, light, and heat, causing structural degradation over time. In this talk, I will first introduce materials strategies to tackle the enduring challenges of long-term stability and device performance simultaneously. Our approach leverages functional molecules that bind to surface defects in various mixed-cation, mixed-anion perovskite compositions. By tailoring the coordination of undercoordinated atoms on the perovskite surfaces as the growth is disrupted, these molecules effectively mitigate interfacial recombination. As a result, our devices approach photovoltages near the Shockley–Queisser limit, yielding voltage deficits below 10 per cent, which is on par with state-of-the-art III–V compound semiconductor technologies. Building on these advances, I will then discuss a vacuum thermal evaporation route tailored for scalable and solvent-free thin-film deposition. This method offers uniform coating over large areas and complex geometries while ensuring robust process control. By carefully tuning the evaporation process, we achieve high-quality perovskite thin films with remarkable crystal orientation and reduced defect densities. These vacuum-processed devices deliver competitive efficiencies and exhibit impressive operational stability. Lastly, I will introduce the operando hyperspectral luminescent techniques that link microscopic photophysics information with macroscopic device performance. Our work charts a path toward closing the gap between laboratory-scale breakthroughs and real-world deployment. Attendees will gain insights into how these complementary strategies foster the development of viable perovskite solar modules that can meet performance and durability benchmarks essential for widespread adoption in the renewable energy landscape. Keywords : Perovskite Solar Cells Corresponding Author : Yen-Hung Lin (yh.lin@ust.hk)	CV
Yeonghun Yun	Helmholtz-Zentrum Berlin	All-perovskite multijunction solar cells with Sn-Pb perovskites based on self-assembled monolayer	Abstract All-perovskite multijunction solar cells with Sn-Pb perovskites based on self-assembled monolayer Yeonghun Yun1, Kevin J. Prince1, Xuan Li1, Sebastian Berwig1, Isabella Taupitz1, Eva Unger1, Philipp Tockhorn1, Steve Albrecht*1 1Helmholtz-zentrum Berlin für Materialien und Energie GmbH All-perovskite multijunction solar cells (APMSCs) stand out as a groundbreaking innovation offering ultra-high theoretical efficiencies, compatibility with flexible devices, and reduced material and energy consumption during fabrication. A key component of APMSCs is Sn-Pb perovskite, with a narrow bandgap (~1.25 eV). Currently, poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) is the standard hole-transport layer (HTL) for Sn-Pb perovskite solar cells. PEDOT:PSS provides high electrical conductivity and adequate energetic alignment for hole-extraction, but limits the current density and stability due to parasitic absorption and its acidic nature. Self-assembled monolayer (SAM) molecules, such as [2-(9H-Carbazol-9-yl)ethyl]phosphonic acid and [4-(3,6-Dimethyl-9H-carbazol-9-yl)butyl]phosphonic acid, provide excellent hole-extraction properties while minimizing optical and non-radiative recombination losses in Pb-based perovskite solar cells. However, they only have recently been applied to Sn-Pb perovskites, and there remains a limited understanding of their effects on Sn-Pb perovskite film formation and device performance. In this work, we systematically investigate the formation of Sn-Pb perovskite films on SAM-based HTLs, provide insight into optical and electronic loss mechanisms, and demonstrate a narrow-bandgap Sn-Pb perovskite solar cell with high a power conversion efficiency (PCE) of up to 22.10%. We reveal, through in-situ photoluminescence measurements, that Sn-Pb perovskite growth on SAM is significantly altered, leading to substantial changes in buried interface. Furthermore, we present high-performance SAM-based triple-junction APMSCs with a PCE beyond 25% benefiting from reduced parasitic absorption losses and thereby an improvement of ~0.6 mA/cm² of the photogenerated current density in the Sn-Pb subcell, showcasing their potential for advanced applications. Finally, we address the challenges and present a strategy for upscaling SAM-based Sn-Pb perovskites and APMSCs using slot-die coating method. Our findings provide a pathway for developing efficient and stable Sn-Pb perovskite solar cells, enabling the practical implementation of APMSCs in next-generation solar technologies. Keywords : perovskite solar cells, multijunction, tandem, Sn-Pb perovskite, self-assembled monolayer Corresponding Author : Steve Albrecht (steve.albrecht@helmholtz-berlin.de)	CV
Han-Don Um	Kangwon National University	Engineering Silicon 3D Nanostructures for Enhanced Photoelectrochemical Cells and Photovoltaics	Abstract Engineering Silicon 3D Nanostructures for Enhanced Photoelectrochemical Cells and Photovoltaics Han-Don Um*1 1Kangwon National University This research focuses on the development of diverse fabrication methodologies for creating 3D silicon nanostructures with applications in energy conversion technologies. We investigate various processing techniques, with particular emphasis on metal-assisted chemical etching (MACE) as a promising approach for precise structural control at the nano/micro scale. Our work explores the optimization of different 3D microstructures tailored for specific energy applications. These silicon microstructures demonstrate potential for enhancing charge transport and catalytic activity in photoelectrochemical (PEC) cells, while also showing advantages in light management for photovoltaic devices. Beyond MACE, we implement complementary fabrication strategies to achieve desired structural features and performance characteristics. This comprehensive approach to 3D silicon nanostructuring provides valuable insights into structure-property relationships for next-generation energy conversion technologies, offering pathways to improved efficiency in both PEC systems and solar cells. Keywords : Silicon, 3D Microstructures, Metal-Assisted Chemical Etching (MACE), Photoelectrochemical Cells, Photovoltaics, Nanofabrication Corresponding Author : Han-Don Um (handon@kangwon.ac.kr)
Beom-Soo Kim	KRICT	Dry Vacuum Processes for Perovskite Solar Cell Fabrication	Abstract Dry Vacuum Processes for Perovskite Solar Cell Fabrication Beom-Soo Kim*1, NamJoong Jeon1 1Korea Research Institute of Chemical Technology Current efforts in thin film deposition focus on achieving compatibility with large-scale applications and high reproducibility. Thermal vacuum deposition, a widely used technique in the semiconductor and OLED industries, has been attempted to apply to hybrid perovskite films. However, controlling the sublimation of perovskite precursors in vacuum process challenges due to abnormal adsorption behaviour, leading to difficulties in control. This presentation will review perovskite fabrication methods using vacuum processes, introduce fully vacuum-processed solar cells, and discuss the growth and deposition kinetics of perovskite films to improve control in vacuum processing. In addition, I will share the latest research on vacuum-processed perovskite solar cells conducted at KRICT, including exceeding 25% efficiency of single junction cells and ~30% of perovksite/Silicon tandem. Keywords : Perovskite solar cell, Vacuum process, Dry process Corresponding Author : Beom-Soo Kim (bkim@krict.re.kr)	CV
Shuzi Hayase	The University of Electro-Communications	Tin-based perovskite solar cells-present status and future-	Abstract Tin-based perovskite solar cells-present status and future- Shuzi Hayase*1 1The University of Electocommunications Tin based perovskite solar cells are expected to have higher potential than lead halide perovskite solar cells (Pb PVK PV) according to the calculated effective mass of carriers and the bandgap. As it stands now, the efficiency and the stability are not as high as that of Pb PVK PV because of lattice defects. In this presentation, approaches to solving these issues are shown by using our approaches. Self-doping with Sn4+ causes a serious decrease in efficiency and stability. Since Sn4+ is located at the bottom and the top of the film, we proposed the insertion of ultrathin Sn metal layer at both sides of the perovskite films 1). In addition to this, the lower efficiency and stability are associated with lattice defects. According to the calculation study, the energy level of p-type defect decreases the efficiency. We designed 5-mercapto-1-methyltetrazole tin salt (2TSn) showing Lewis base properties and proved that the additive is effective for enhancing the efficiency of Sn PVK PV. The efficiency improved from 12.86 % to 15.33 % after the 2TSn was added 2). The stability at 85 ℃ was improved by decreasing the defect density and suppressing the ion migration. In the presentation, possibility of lead free perovskite tandem is also discussed. References (1) Liang Wang, Huan Bi, Jiaqi Liu, Yuyao Wei, Zheng Zhang, Mengmeng Chen, Ajay Kumar Baranwal, Gaurav Kapil, Takeshi Kitamura, Shuzhang Yang, Qingqing Miao, Qing Shen, Tingli Ma, Shuzi Hayase, ACS Energy Lett. 2024, 9, 12, 6238–6244. (2) Liang Wang, Huan Bi, Jiaqi Liu, Yuyao Wei, Zheng Zhang, Mengmeng Chen, Ajay Kumar Baranwal, Gaurav Kapil, Takeshi Kitamura, Shuzhang Yang, Qingqing Miao, Qing Shen, Tingli Ma, Shuzi Hayase, ACS Energy Lett. 2024, 9, 12, 6238–6244. Keywords : tin perovskite solar cell, lead free, tandem, surface passivation, efficeincy, stability Corresponding Author : Shuzi Hayase (hayase@uec.ac.jp)	CV
Jung-Kun Lee	University of Pittsburgh	Enhanced light management in perovskite-silicon tandem solar cells by optically engineered anti-reflective film	Abstract Enhanced light management in perovskite-silicon tandem solar cells by optically engineered anti-reflective film Jung-Kun Lee*1, Kyoung-Jin Choi2 1University of Pittsburgh, 2UNIST Designing an efficient optical path for perovskite-silicon tandem cells is a crucial yet often overlooked strategy to enhance light-to-electricity conversion. When light strikes the top perovskite layer of the tandem cell, the incident light experiences reflection loss at the air-perovskite interface, which occurs because of the difference in refractive indices. To mitigate this, a thin antireflection coating of fluoride materials is often applied to the top of the tandem solar cells. However, the effectiveness of a flat antireflection layer is limited, and some surface reflection persists. To further reduce this, textured poly(dimethylsiloxane) (PDMS) films are tested on top of the TCO. While these textured films enhance light scattering internally, PDMS does not have a refractive index that optimally matches the TCO and air interface. To overcome key challenges in optical design, an effective textured antireflection layer must minimize surface reflection while converting potentially harmful UV light into useful visible light. In this study, a composite material incorporating (Ba, Ca, Eu, Sr)₂SiO₄ (referred to as SGA) phosphors and SiO₂ nanoparticles, is embedded within textured PDMS. This composite enhances UV light conversion and increases diffuse transmittance. The combination of SGA phosphors and SiO₂ nanoparticles significantly reduces reflection while mitigating the parasitic absorption of UV light. As a result, the textured PDMS-nanoparticle composite effectively boosts the efficiency of perovskite/Si tandem solar cells. Such PCE enhancement is primarily driven by an increase in short-circuit current density, which stems from reduced reflectance and optimized UV light utilization. The findings of this work provide a strategic approach to designing advanced antireflection coatings to enhance the optical performance of tandem solar cells. Keywords : tandem solar cell, anti-reflection coating, multiple scattering Corresponding Author : Jung-Kun Lee (jul37@pitt.edu)	CV
Kwanyong Seo	UNIST	Transparent Crystalline Silicon Solar Cells and Modules	Abstract Transparent Crystalline Silicon Solar Cells and Modules Kwanyong Seo*1 1Ulsan National Institute of Science and Technology (UNIST) Transparent solar cells, which combine both visible transparency and solar energy conversion, are being developed for applications where conventional opaque solar cells are not feasible, such as the windows of buildings or vehicles. However, the transparent solar cells developed so far have limitations in efficiency and stability. Crystalline silicon (c-Si) is a leading candidate for developing transparent solar cells with proven high efficiency and long-term stability, since conventional c-Si solar cells outperform other solar cell technologies in these metrics. However, the opaque nature of the c-Si wafer hinders the development of transparent solar cells based on c-Si. In this presentation, I will introduce a novel approach to developing neutral-colored, transparent c-Si solar cells that exhibit the highest efficiency among such cells developed to date. From fundamental research to the commercialization of transparent solar cells, three main perspectives should be considered: (1) high power conversion efficiency at a given average visible transmittance; (2) aesthetic factors that should not detract from applications such as buildings and vehicles; and (3) feasibility for real-world applications, including modularization and stability evaluation. I will present specific analysis criteria for these perspectives and discuss their importance. Keywords : transparent, solar cells, c-Si, module, BIPV Corresponding Author : Kwanyong Seo (kseo@unist.ac.kr)	CV
Dae-Kue Hwang	DGIST	Influence of the Electron Transport Layer and Interconnection Layer in Perovskite/Copper Indium Gallium Selenide Hybrid Tandem Solar Cells	Abstract Influence of the Electron Transport Layer and Interconnection Layer in Perovskite/Copper Indium Gallium Selenide Hybrid Tandem Solar Cells Dae-Kue Hwang*1, Kumar Naveen1, Jaebaek Lee1, Hyo Jeong Jo1, Shi-Joon Sung1, Kee-Jeong Yang1, Jin-Kyu Kang1, Dae-Hwan Kim1 1Daegu Gyeongbuk Institute of Science and Technology Organic–inorganic hybrid perovskite materials have emerged as exceptional candidates for light absorbers in tandem solar cells, owing to their tunable bandgaps, high absorption coefficients, low fabrication costs, and simple manufacturing processes. Tandem solar cell architectures offer a promising route to enhance efficiency and reduce costs for practical photovoltaic applications. However, the development of two-terminal perovskite-based tandem devices faces critical challenges, including the optimization of semitransparent perovskite devices and the interconnection between sub-cells. Achieving high efficiency in these tandem structures requires simultaneous fulfillment of stringent electrical, optical, and chemical criteria. This study explores recent advancements in semitransparent perovskite layers and interconnection strategies for two-terminal perovskite-based tandem solar cells. The findings highlight key technological improvements and identify future research directions to address existing limitations. A concise summary of current progress and potential pathways is also provided. Keywords : Perovskite, Copper Indium Gallium Selenide, semitransparent, Tandem solar cells Corresponding Author : Dae-Kue Hwang (dkhwang@dgist.ac.kr)	CV

13 XIII. Water splitting, CO2 reduction

Keynote Speakers

Heechae Choi

Xi'an Jiaotong-Liverpool University

Cost-effective atomic-scale modeling of photocatalytic and photoelectrocheimcal reactions for water splitting and CO2 reductions on heterojunctioned systems with multiple engineering factors

Abstract

Cost-effective atomic-scale modeling of photocatalytic and photoelectrocheimcal reactions for water splitting and CO2 reductions on heterojunctioned systems with multiple engineering factors

Heechae Choi*1

1Xi'an Jiaotong-Liverpool University

Heterojunctioned nanomaterials are widely used in photocatalytic and photoelectrochemical (PEC) reactions for eco-friendly energy productions. Synergies of defect engineering, composite formation, and morphology control of heterojunctioned nanomaterial systems can greatly increasd the yield amount of valuable chemicals through photocheimcal reactions. In many cases, however, the materials design principles for single engineering factors are not valid anymore when multiple materials engineering factors are applied simultaneously. Therefore, it is very challenging to rationalize the strategies of multiple materials modification methods to achieve the highest energy conversion efficiency. In this presentation, I will introduce recent research works on modeling method developments for photochemical water splitting and CO2RR of metal-semiconductor and metal-metal heterojunctions having multiple engineering factors.

Keywords : Modeling, Energy conversion, Photochemistry

Corresponding Author : Heechae Choi (heechae.choi@xjtlu.edu.cn)

CV

Xin TU

Liverpool University

Plasma Catalysis: An Emerging Electrification Solution for CO2 Conversion

Abstract

Plasma Catalysis: An Emerging Electrification Solution for CO2 Conversion

Xin Tu

Department of Electrical Engineering and Electronics, University of Liverpool, Liverpool L69 3GJ, UK

xin.tu@liv.ac.uk

The conversion of CO2 into valuable fuels and chemicals presents a crucial strategy for mitigating climate change and fostering a circular carbon economy. However, CO2 is an inert and stable molecule with strong chemical bonds, thus requiring considerable energy input for its activation. Non-thermal plasma (NTP) has emerged as a promising electrification technology for CO2 conversion under ambient conditions. The combination of NTP with heterogeneous catalysis holds great potential for achieving synergistic effects through interactions between the plasma and catalysts. This interaction can activate catalysts at low temperatures, enhancing their activity and stability and leading to a notable increase in conversion, selectivity, and yield of end-products. Additionally, it can improve the energy efficiency of the process. Furthermore, plasma processes can be instantly switched on and off, offering flexibility for decentralized production of fuels and chemicals with significantly reduced capital costs, using renewable energy sources, particularly intermittent renewable energy. This presentation will discuss the challenges and opportunities in plasma-catalytic conversion of CO2 to fuels and chemicals, including various CO2 conversion routes such as CO2 splitting, CO2 hydrogenation, and CO2 dry reforming of CH4. By unlocking the potential of CO2 as a valuable resource, plasma catalysis holds immense promise for a sustainable future. This talk aims to inspire further exploration and development of this transformative technology.

CV

Katsushi Fujii

RIKEN

Stability of electrochemical CO2 reduction in a zero-gap reactor compared with water electrolysis

Abstract

Stability of electrochemical CO2 reduction in a zero-gap reactor compared with water electrolysis

Katsushi Fujii*1, Takeharu Murakami1, Kei Morishita1, Miyuki Nara1, Takeshi Matsumoto1, Takayo Ogawa1, Satoshi Wada1

1RIKEN RAP

The stability of electrochemical CO2 reduced reaction (CO2RR) with zero-gap reactors is one of the problems that need to be realized in establishing the technique. The main problem is salt precipitation, which prevents CO2 supply to the CO2-reduced catalyst region, and electrolyte flooding in the cathode. These problems are not observed in cation exchange membrane water electrolysis (PEMWE), which is similar to the cell structure of the zero-gap reactor.
Since the evaluations of the salt precipitation and flooding are the first step to understanding the reasons, the cell with a transparent cathode endplate was fabricated to observe the inside of the cathode. Voltage oscillations of about 40-min period by constant current supply were observed when the transparent cathode endplate cell was used. It was found that the CO2RR occurred at the higher voltage, and the hydrogen evolution reaction (HER) occurred at the lower voltage. This oscillation was observed in a relatively wide current density region (100 – 300 mA/cm2), and current oscillation was also observed with constant voltage application. The mode change from CO2RR to HER is probably the reduction of CO2 supply, mainly by the flooding. The reason for the mode change from HER to CO2RR is still obscure, however, this change is likely related to the material transportation change since the dissolving of salt and the decreasing of flooding were observed at HER.
The electro osmosis, and the water and cation diffusion due to the electrolyte concentration difference were estimated to be the main material transportation from the model experiments with H-type cell. Both cation and water transportation are found to have the cross point from anode to cathode to cathode to anode, depending on the catholyte concentration. The mode change from HER to CO2RR is probably related to this material transportation condition change.

Keywords : Water electrolysis, CO2 reduced reaction, Stability

Corresponding Author : Katsushi Fujii (katsushi.fujii@riken.jp)

CV

Invited Speakers

Name	Affiliation	Title	Abstract	CV
Wan Jae Dong	Korea University	Solar-Driven Hydrogen Evolution and Ammonia Production via GaN Nanowire Photoelectrodes	Abstract Solar-Driven Hydrogen Evolution and Ammonia Production via GaN Nanowire Photoelectrodes Wan Jae Dong*1 1Korea University Solar-driven photoelectrochemical processes offer a sustainable route for converting solar energy into valuable chemical fuels. In this study, we report on the development of gallium nitride nanowires (GaN NWs)-based photoelectrodes engineered for efficient proton-coupled electron transfer (PCET) under solar illumination. By strategically integrating co-catalysts (platinum, gold, and cobalt oxide) onto the GaN NWs, our system achieves enhanced charge separation, elevated photocurrent densities, and improved reaction selectivity. Comprehensive spectroscopic and electrochemical analyses indicate that the PCET reactions induce in-situ surface modification of the GaN NWs. This modification leads to the formation of Ga-O-N species, which are crucial for maintaining robust hydrogen evolution performance over extended periods (exceeding 3,000 hours). Our findings also highlight the synergistic interaction between semiconductor nanostructures and co-catalysts, establishing GaN NWs as a scalable and durable platform for green ammonia synthesis through nitrate reduction reaction. This work not only advances the fundamental understanding of PCET mechanisms at semiconductor-catalyst interfaces but also opens new avenues for the sustainable production of green hydrogen and ammonia. Keywords : photoelectrochemistry, green hydrogen, ammonia, gallium nitride Corresponding Author : Wan Jae Dong (wjdong@korea.ac.kr)	CV
Jung Kyu Kim	Sungkyunkwan University	Transition Metal-Based Electrocatalysts with Tailored Interfacial Structure for Water Electrolysis	Abstract Transition Metal-Based Electrocatalysts with Tailored Interfacial Structure for Water Electrolysis Jung Kyu Kim*1 1Sungkyunkwan University Water electrolysis is a promising technology for sustainable hydrogen production, yet its widespread adoption is hindered by the high overpotential and limited durability of electrocatalysts. Transition metal-based materials have emerged as key candidates due to their cost-effectiveness, abundance, and tunable catalytic properties. However, further improvements in catalytic efficiency and long-term stability are essential for practical applications. In this presentation, I explore the role of interfacial structure engineering in enhancing the performance of transition metal-based electrocatalysts for water electrolysis. By strategically modulating the electronic structure, optimizing active site exposure, and engineering surface chemistry, significant enhancements in reaction kinetics and durability can be achieved. Specifically, I discuss approaches such as heterostructure formation, defect engineering, and atomic-level interface modification, which facilitate improved charge transfer and intermediate adsorption behavior. These advancements in catalyst design not only contribute to more efficient and stable water electrolysis systems but also pave the way for scalable and economically viable hydrogen production. By leveraging interfacial engineering strategies, I can bridge the gap between fundamental electrochemical research and practical implementation, accelerating the transition toward a sustainable energy future. Keywords : electrocatalysts, water splitting, hydrogen, energy conversion Corresponding Author : Jung Kyu Kim (legkim@skku.edu)	CV
Xiaoyan Lu	Luoyang Normal University	Synergistic Dual Electron Transfer Pathways and LSPR-Induced Photothermal Effects in Ternary Heterojunction for Boosting Photocatalytic Hydrogen Evolution	Abstract Synergistic Dual Electron Transfer Pathways and LSPR-Induced Photothermal Effects in Ternary Heterojunction for Boosting Photocatalytic Hydrogen Evolution Xiaoyan Lu*1, Shuang Wang1, Ying Zhao1 1College of Chemistry and Chemical Engineering, Henan Key Laboratory of Function-Oriented Porous Materials, Luoyang Normal University It is an inherent problem in the field of photocatalytic hydrogen (H2) production to develop multi-component composite materials to simultaneously overcome narrow light absorption range, weak carrier separation ability, and slow interfacial reaction kinetics. Using the monolayer plasmonic Ti3C2Tx with strong LSPR photothermal effect as substrate, we synthesized the first example of a ternary heterojunction nanocomposite containing O and S dual vacancies via a two-step hydrothermal method. Dual electron transfer of multi-component 2D interface heterojunctions, O and S dual vacancies, and Ti3C2Tx LSPR photothermal effect synergistically enhance light absorption, migration of photogenerated charge carriers, and surface reaction rates. In addition, the photothermal surface temperature obtained by ternary heterojunction nanocomposite under illumination far exceeds that obtained by the original Ti3C2Tx. Through DFT and FDTD methods, it is proved that high density electron transfer and large area strong LSPR coupling are realized through 2D interfacial heterojunction and dual vacancies, and the LSPR photothermal effect of Ti3C2Tx is effectively enhanced. Our work provides important insights into the construction of 2D multi-component plasmonic co-catalyst/semiconductor systems and the explanation of the LSPR electromagnetic field enhancement mechanism. The efficient LSPR photothermal effect provides a reasonable inspiration for the design of photocatalysts in extremely cold environments. Keywords : ternary heterojunction; electron transfer, photocatalysis, Hydrogen Evolution Corresponding Author : Xiaoyan Lu (zklxiaoyan@163.com)	CV
Yanwei Lum	National University of Singapore	TBD
Eric Han	Stanford University	Texture Engineering in Photoanodes: A Breakthrough for Efficient Solar Water-Splitting	Abstract Texture Engineering in Photoanodes: A Breakthrough for Efficient Solar Water-Splitting Hyun Soo Han*1 1Stanford University Solar water-splitting holds great promise for efficient solar energy conversion and storage. A major technical challenge in solar water-splitting is the limited efficiency of photoanodes in generating charge carriers that drive water oxidation to oxygen. Various strategies have been explored to enhance the performance of photoanodes in solar water oxidation, with texture engineering emerging as a particularly promising approach. By tuning crystallographic orientation and exposed facets, texture engineering improves charge transport and minimizes surface recombination, ultimately enhancing photoelectrochemical water-splitting efficiency. This presentation will highlight advancements in photoanode development, focusing on how texture engineering improves charge carrier dynamics and enhances photoelectrochemical water-splitting performance. Keywords : Solar water-splitting, Texture Engineering, Photoanode Corresponding Author : Hyun Soo Han (erichan1@stanford.edu)	CV
Kyoungsuk Jin	Korea University	Electrochemical olefin epoxidation coupled with H2 evolution	Abstract Electrochemical olefin epoxidation coupled with H2 evolution Kyoungsuk Jin*1 1Korea University Over several decades, electrochemistry has played an imperative role in synthetic chemistry. Starting from the Kolbe reaction, developed in 1848, a lot of effort has been devoted to synthesizing target products with the use of electrochemistry. However, although electrochemical organic synthesis can be driven with environmentally friendly sources of electricity, only a small number of commodity chemicals have been produced via electrochemical reactions; namely, anthraquinone, some perfluorinated hydrocarbons (PFCs), and adiponitrile, a key intermediate for the polymer Nylon 6,6. Most research into these synthetic approaches is just at the laboratory or pilot scale. The fact that such minimal attention has been paid to the commercialization of these methods has been attributed to high energy costs due to the required large overpotential values and poor selectivity toward desired products. In this regard, we should focus on addressing challenging electro-organic synthesis problems through engineering efficient catalysts and gaining a deeper understanding of reaction mechanisms on those catalysts. In this talk, I will present our recent studies about olefin epoxidation coupled with water reduction reaction. Keywords : Epoxidation, Electrosynthesis Corresponding Author : Kyoungsuk Jin (kysjin@korea.ac.kr)	CV
Chungsuk Choi	Sungkyunkwan University	Advanced Materials for Energy and Environmental Sustainability	Abstract Advanced Materials for Energy and Environmental Sustainability Chungsuk Choi*1 1Sungkyunkwan University Harvesting alternative clean energy and remedying the earth from pollutants is of critical importance as we seek to curb the global reliance on fossil fuels and prevent further ecological destruction that threatens human life. Energy and environmental sustainability can be achieved via closed-loop recycling that captures environmental pollutants (e.g., CO2 and persistent water pollutants) and converts them into fuels or chemicals. Such a process can simultaneously create valuable products while also removing harmful pollutants from the environment. However, the lack of effective catalysts for conversion limits the development of closed-loop recycling. I will present design strategies for advanced nanomaterials and hybrid materials for effective electrochemical and photochemical conversion of environmental pollutants into value-added products that store chemical energy. In the first part of the talk, I will discuss how to incorporate structure defects into Cu nanomaterials. The Cu defect sites are recognized as highly active sites for electrochemical CO2 reduction into hydrocarbon products, but it is a challenge to keep the defect sites during the reaction because of their structural instability. I will discuss materials approaches to utilize the highly active defective catalytic sites for electrochemical CO2 reduction without instability issues. Next, I will discuss the opportunities to purify persistent water pollutants while at the same time recovering valuable hydrocarbon molecules. I developed an organometallic molecule/nanomaterial assembly, comprised of cobalt phthalocyanine (CoPc) molecules assembled on multiwalled carbon nanotubes (CNTs), that electrochemically converts 1,2-dichloroethane (DCA) into ethylene. DCA is one of the most widely produced chemicals in the world but also a persistent toxic environmental pollutant with notorious health risks and a long half-life in the environment. The nanotubular structure of the catalyst enables us to shape it into a scalable flow-through electrified membrane, which we have used to demonstrate >95% DCA removal from simulated water samples with environmentally relevant DCA and electrolyte concentrations. Finally, I will introduce a ternary hybrid photocatalyst, comprising CoPc molecules assembled on CNTs with CdS quantum dots (QDs) that enables photochemical upgrading of air-captured CO2 to CO. The ternary photocatalyst with the CO2-capturing system skips the otherwise energy-demanding CO2 separation process and offers pragmatic carbon capture and recycling opportunities through photochemical CO2 reduction. Keywords : CO2 Reduction, Catalyst, Carbon Neutral Corresponding Author : Chungsuk Choi (cs.choi@skku.edu)	CV
Chengkai Xia	North University of China	Photoelectrochemical Value-added Reactions for Green Solar-to-Chemical Energy Conversions	Abstract Photoelectrochemical Value-added Reactions for Green Solar-to-Chemical Energy Conversions Chengkai Xia*1 1North University of China Facing climate change and the fossil fuel crisis, the global need for clean energy is more urgent than ever. Converting solar energy to produce green hydrogen fuel through photoelectrochemical (PEC) water splitting is a feasible strategy for utilizing solar energy, aligning with the increasing global demand for clean energy production. However, the energy conversion efficiency and overall economic benefit are severely limited by the slow kinetics of the oxygen evolution reaction (OER) and the low profitability of oxygen production, hindering the commercial utilization of PEC energy conversion technology. In the past few years, studies focusing on replacing the OER with PEC value-added reactions, which can produce high-value products, have received great attention. This not only improves the economic benefits of the general reaction system but also enhances the energy conversion efficiency. In this presentation, the basic principles of PEC value-added reactions and feedstock-product cost analysis are introduced first. Then, the latest research progress of our lab on PEC glycerol oxidation and ammonia splitting is summarized and discussed in detail. Finally, the status of commercial applications, further prospects, and challenges are discussed. Keywords : PEC, ammonia splitting, glycerol oxidation, solar-to-hydrogen Corresponding Author : Chengkai Xia (ckxia@nuc.edu.cn)	CV
Danlei Li	Xi'an Jiaotong-Liverpool University	Localised Negatively Charged Interfaces in Chlorine-doped Fe/Carbon single atom catalyst toward oxygen reduction in seawater	Abstract Localised Negatively Charged Interfaces in Chlorine-doped Fe/Carbon single atom catalyst toward oxygen reduction in seawater Danlei Li*1, Wenhan Fang3, Jun Wu2 1Xi'an Jiaotong-Liverpool University, 2Central South University, 3Xi'an Jiaotong-Liverpool Unviersity The oxygen reduction catalyst is a critical component of seawater metal-air batteries, as its catalytic performance directly determines the energy conversion efficiency of the battery. However, the adsorption of chloride ions (Cl⁻) during the oxygen reduction reaction (ORR) in seawater severely poisons conventional catalysts, limiting their performance. To address this challenge, this project focuses on the design of a novel, efficient, and stable catalyst that resists Cl⁻ poisoning. We successfully synthesized a chlorine-doped iron-supported carbon-based catalyst (Cl-Fe-ODAN), which introduces Cl⁻ to create a locally negatively charged interface. This interface effectively repels Cl⁻ ions, preventing catalyst poisoning even in high-concentration Cl⁻ environments. Comprehensive material characterization and electrochemical testing revealed that the catalyst exhibits a high current density and a low half-wave potential for ORR. Moreover, the catalyst demonstrates exceptional stability, maintaining consistent current density and half-wave potential over 150 cycles in an alkaline electrolyte containing 0.5 M Cl⁻ ions and sythetic seawater. These results highlight the potential of Cl-Fe-ODAN as a high-performance, Cl⁻-resistant catalyst for seawater metal-air batteries. Keywords : single atom catalyst; seawater; oxygen reduction reaction Corresponding Author : Danlei Li (danlei.li@xjtlu.edu.cn)	CV
Changho Yoo	Unist	Organometallic Strategies for Sustainable CO2 and CO Conversion	Abstract Organometallic Strategies for Sustainable CO2 and CO Conversion Changho Yoo*1 1Ulsan National Institute of Science and Technology The catalytic conversion of C1 chemicals such as CO₂ and CO has garnered significant attention for addressing energy sustainability and environmental challenges. Despite the development of numerous catalytic systems, current methods still face challenges, including low activity, limited selectivity, and the reliance on precious metals. While heterogeneous catalysts dominate industrial applications, many advanced organic syntheses and challenging transformations still rely heavily on homogeneous catalysis. This highlights the potential of fundamental organometallic chemistry to address the limitations of C1 conversion. In this presentation, we will discuss organometallic approaches to developing sustainable CO₂ and CO conversion. The first section will highlight strategies for developing homogeneous catalysts guided by mechanistic understanding. This will include the utilizing earth-abundant metals for carbonylation, enhancing selectivity in olefin oligomerization, and discovering new carboxylation reactions using CO₂. The second section will focus on the application of organometallic principles to heterogeneous catalysis. This includes the heterogenization of organometallic catalysts, interpreting heterogeneous systems and designing innovative catalytic reactions informed by organometallic insights. Keywords : organometallic catalysts, homogeneous catalysis, CO2, CO Corresponding Author : Changho Yoo (cyoo@unist.ac.kr)	CV
Younghyun Hong	Sogang University	Development of Sustainable Catalytic System for Generation of Value-added Products from Natural Abundant Resources	Abstract Development of Sustainable Catalytic System for Generation of Value-added Products from Natural Abundant Resources Young Hyun Hong1 1Sogang University Artificial photosynthesis has been the current major challenge, aiming at the conversion of solar energy into solar fuels by mimicking principles of natural photosynthesis. In this talk, I will briefly summarize my comprehensive research on artificial photosynthesis. We have developed molecular functional models of photosystems I and II, as well as a combination of these models, that achieve water splitting and NADPH production based on molecular photocatalysis.1–4 Characterization and reactivity studies of reaction intermediates have been performed in photocatalytic water oxidation and photocatalytic water reduction to produce H2, as well as in NAD+ reduction to NADH to elucidate the mechanisms.1–4 The redox cycle of plastoquinone and plastoquinol analogs has also been studied in homogeneous artiﬁcial photosynthesis as a way to mimic natural photosynthesis.1–4 Moreover, we reported the ﬁrst example of capturing all key intermediates and monitoring the dynamics in catalytic water-oxidation reactions by biomimetic catalysts, providing valuable mechanistic insights into the catalytic four-electron oxidation of water to evolve O2.5 Inspired by the oxygen-evolving complex in PSII, extensive efforts have so far been devoted to identifying the nature of intermediates and the O–O bond-formation mechanism in photocatalytic water oxidation. We reported the capture and identiﬁcation of the key intermediates and the O–O bond-formation step in the catalytic water oxidation by the excited state of 2,3-dichloro-5,6-dicyano-p-benzoquinone (3DDQ) with a nonheme iron complex.5 In particular, two key intermediates, an iron(V)-oxo and an iron (III)-hydroperoxo species, were captured in the water oxidation reactions.5 To the best of our knowledge, this study provides the ﬁrst valuable mechanistic insights into the O–O bond-formation step in water oxidation by a nonheme iron catalyst through the detection of all intermediates and a kinetics study of the isolated intermediates.5 References 1. “Photodriven Oxidation of Water by Plastoquinone Analogs with a Nonheme Iron Catalyst”, Y. H. Hong, J. Jung, T. Nakagawa, N. Sharma, Y.-M. Lee, W. Nam* and S. Fukuzumi, J. Am. Chem. Soc. 2019, 141, 6748−6754. 2. “Photocatalytic Hydrogen Evolution from Plastoquinol Analogues as a Potential Functional Model of Photosystem I”, Y. H. Hong, Y.-M. Lee, W. Nam and S. Fukuzumi, Inorg. Chem. 2020, 59, 14838−14846. 3. “Molecular Photocatalytic Water Splitting by Mimicking Photosystems I and II” Y. H. Hong, Y.-M. Lee, W. Nam and S. Fukuzumi, J. Am. Chem. Soc. 2022, 144, 695−700. 4. “Artificial Photosynthesis for Regioselective Reduction of NAD(P)+ to NAD(P)H Using Water as an Electron and Proton Source” Y. H. Hong, M. Nilajakar, Y.-M. Lee, W. Nam and S. Fukuzumi, J. Am. Chem. Soc. 2024, 146, 5152–5161. 5. “Seeing the Key Intermediates in Bioinspired Nonheme Iron Complex-Catalyzed Water Oxidation” Y. H. Hong, Y.-M. Lee, S. Fukuzumi, and W. Nam, Chem 2024, 10, 1755-1765. Keywords : artificial photosynthesis, water splitting, O-O bond formation, photocatalysis, NADP+ reduction Corresponding Author : Young Hyun Hong (yhhong@sogang.ac.kr)Inspired by the oxygen-evolving complex in PSII, extensive efforts have so far been devoted to identifying the nature of intermediates and the O–O bond-formation mechanism in photocatalytic water oxidation. We reported the capture and identiﬁcation of the key intermediates and the O–O bond-formation step in the catalytic water oxidation by the excited state of 2,3-dichloro-5,6-dicyano-p-benzoquinone (3DDQ) with a nonheme iron complex.5 In particular, two key intermediates, an iron(V)-oxo and an iron (III)-hydroperoxo species, were captured in the water oxidation reactions.5 To the best of our knowledge, this study provides the ﬁrst valuable mechanistic insights into the O–O bond-formation step in water oxidation by a nonheme iron catalyst through the detection of all intermediates and a kinetics study of the isolated intermediates.5 References 1. “Photodriven Oxidation of Water by Plastoquinone Analogs with a Nonheme Iron Catalyst”, Y. H. Hong, J. Jung, T. Nakagawa, N. Sharma, Y.-M. Lee, W. Nam* and S. Fukuzumi, J. Am. Chem. Soc. 2019, 141, 6748−6754. 2. “Photocatalytic Hydrogen Evolution from Plastoquinol Analogues as a Potential Functional Model of Photosystem I”, Y. H. Hong, Y.-M. Lee, W. Nam and S. Fukuzumi, Inorg. Chem. 2020, 59, 14838−14846. 3. “Molecular Photocatalytic Water Splitting by Mimicking Photosystems I and II” Y. H. Hong, Y.-M. Lee, W. Nam and S. Fukuzumi, J. Am. Chem. Soc. 2022, 144, 695−700. 4. “Artificial Photosynthesis for Regioselective Reduction of NAD(P)+ to NAD(P)H Using Water as an Electron and Proton Source” Y. H. Hong, M. Nilajakar, Y.-M. Lee, W. Nam and S. Fukuzumi, J. Am. Chem. Soc. 2024, 146, 5152–5161. 5. “Seeing the Key Intermediates in Bioinspired Nonheme Iron Complex-Catalyzed Water Oxidation” Y. H. Hong, Y.-M. Lee, S. Fukuzumi, and W. Nam*, Chem 2024, 10, 1755-1765. Keywords : artificial photosynthesis, water splitting, O-O bond formation, photocatalysis, NADP+ reduction Corresponding Author : Young Hyun Hong (yhhong@sogang.ac.kr)	CV
Yang Yang	Nanjin Tech University	Improving Photoelectrochemical Water Splitting Performance of TiO2 Nanowire Arrays by Defect Modulation in Nonepitaxial Cladding Layers	Abstract Improving Photoelectrochemical Water Splitting Performance of TiO2 Nanowire Arrays by Defect Modulation in Nonepitaxial Cladding Layers Yang Yang* State Key Laboratory of Materials-Oriented Chemical Engineering & College of Chemical Engineering, Nanjing Tech University, China *E-mail: yangy@njtech.edu.cn Hydrogen generation by water splitting is one possible energy storage solution that enables deeper integration of renewable resources. Rutile titania (TiO2) has a wide band gap of 3.0 eV and a considerably positive valence band position vs. NHE. In view of water oxidation as the bottleneck step in water splitting, an adequate overpotential obtained by ultraviolet (UV) irradiation on TiO2 provides the possibility to drive water oxidation in a wide pH range. Direct growth of oriented rutile TiO2 single-crystal nanowire arrays could be readily achieved on transparent conductive FTO glass substrates by low-temperature hydrothermal reactions. This synthetic process facilitates the fabrication of photoanodes derived from TiO2 nanowire arrays for photoelectrochemical (PEC) generation of solar hydrogen. Coupling functional thin layers with TiO2 nanowires is an efficient approach to tuning the photoelectric properties of both the parties. In this report, we demonstrate efficient processes for boosting PEC water splitting performance of TiO2 nanowire arrays by constructing specific core–shell interfaces with nonepitaxial cladding layers. Firstly a carbon dots-embedded metal oxide amorphous shell is constructed on TiO2 nanowires by a one-step hydrothermal method. Secondly a TiO2 shell that is rich in oxygen vacancy is formed on TiO2 nanowires by thermal treatment of magnetron sputtered Ti thin film. Thirdly a core–shell heterostructure with TiO2 nanowire as core and the MOF NTU-9 as shell is synthesized via a surfactant-free solution approach. By implementation of the above samples as photoanodes under full spectrum light illumination, significantly enhanced photoresponse and PEC hydrogen production efficiency is achieved in each case. We explicate the specific mechanisms relevant to defect modulation for spacial separation of photogenerated electron–hole pairs in TiO2 nanowires and propose how the core–shell interfaces inform the performance of TiO2-based composites for PEC applications. Keywords. PEC water splitting, TiO2 nanowire arrays, core–shell heterostructures, defect modulation, nonepitaxial growth	CV
Ali (Rouhollah) Jalili	University of New South Wales	Green ammonia synthesis via air-plasma oxidation and electrocatalytic reduction for hydrogen transport	Abstract Green ammonia synthesis via air-plasma oxidation and electrocatalytic reduction for hydrogen transport Ali Jalili*1 1University of New South Wales The production of ammonia using renewable energy in a decentralized manner is critical for a sustainable future. Aside from its critical role as a key ingredient in fertilizers, ammonia is increasingly important as a hydrogen carrier for energy storage and transport, providing a carbon-free way to harness the potential of intermittent renewable resources. However, conventional ammonia synthesis via the Haber-Bosch process remains highly energy-intensive and dependent on fossil-derived hydrogen, necessitating the search for alternative, environmentally friendly approaches. We present a hybrid strategy that combines non-thermal plasma and electrocatalysis to synthesize ammonia directly from air and water, overcoming many of the limitations associated with traditional methods. This approach relies on a plasma reactor powered by a nanosecond pulse power supply to directly interface plasma with water, allowing for a thorough investigation of gas ionization processes, energy transfer pathways, and reactive species formation in both gas and liquid phases. By utilizing advanced catalysts and materials engineered carefully for plasma-assisted reactions and subsequent electrocatalytic reduction steps, we significantly improve the energy efficiency of this hybrid system, lowering operational costs and emissions. In addition to its promise for fertilizer production, this plasma-electrochemical route contributes to ammonia's broader role as a versatile hydrogen carrier. Ammonia's relatively high energy density, ease of liquefaction, and compatibility with existing infrastructure make it an appealing medium for storing and transporting hydrogen, easing the integration of renewables into power grids and industrial processes. Our findings show that by carefully regulating energy input via pulsed plasma ignition and optimizing catalyst design, we can achieve high-performance ammonia production and lay the groundwork for industrial-scale adoption. Keywords : Plasma catalysis, electrocatalysts, green ammonia as hydrogen carrier. Corresponding Author : Ali Jalili (ali.jalili@unsw.edu.au)	CV

14 XIV. Implantable Biointegrated Materials and Devices for Personalized Medicine

Keynote Speakers

Jia Liu

Harvard University

Soft and flexible bioelectronics for brain-machine interfaces

Abstract

Soft and flexible bioelectronics for brain-machine interfaces

Large-scale brain mapping through brain-machine interfaces is important for deciphering neuron dynamics, addressing neurological disorders, and developing advanced neuroprosthetics. Ultimately, brain mapping aims to simultaneously record activities from millions, if not billions, of neurons with single-cell resolution, millisecond temporal resolution and cell-type specificity, across three-dimensional (3D) brain tissues over the course of brain development, learning, and aging. In this talk, I will first introduce the development of flexible and soft bioelectronics with tissue-like properties that can track electrical activity from the same neurons in the brain of behaving animals over their entire adult life. Specifically, I will discuss the fundamental limitations of the electrochemical stability of soft electronic materials in bioelectronics and present our strategies to overcome these limitations, enabling a scalable platform for large-scale, long-term, stable brain mapping. Then, I will discuss the creation of “cyborg organisms”, achieved by embedding stretchable mesh-like electrode arrays in 2D sheets of stem/progenitor cells and reconfiguring them through 2D-to-3D organogenesis, which enables continuous 3D electrophysiology during the development of human stem cell-derived brain organoids and animal embryonic brains. Next, I will highlight our translational efforts to apply these flexible and soft bioelectronics in brain-computer interfaces and deep tissue stimulation for clinical applications. Finally, I will discuss our recent efforts integrating 3D single-cell spatial transcriptomics, machine learning, and electrophysiology to enable cell-type-specific brain activity mapping. Look ahead, I will discuss the fusion of soft and flexible bioelectronics, spatial transcriptomics, and AI to create a comprehensive brain cell functional atlas, advancing the future of brain-machine interface and neurotechnology.

CV

Bozhi Tian

University of Chicago

Photoelectroceuticals: Materials, Devices, and Applications

Abstract

Photoelectroceuticals: Materials, Devices, and Applications

Bozhi Tian*1, Pengju Li1

1University of Chicago

The field of implantable electronic and photonic biointerfaces is undergoing a revolutionary transformation, fueled by interdisciplinary approaches that integrate materials science, biophysics, and bioengineering. This convergence is driving the development of implantable—and even “living”—bioelectronic systems with the potential to radically transform in vivo electrophysiology, sensing, and regenerative medicine, including the emerging field of photoelectroceuticals.
Our laboratory has achieved several significant milestones that underscore the translational impact of applying physical biology to implantable technologies and photoelectroceuticals. Our advanced devices enable targeted photostimulation in clinical settings by leveraging novel material systems such as nanoporous and non-porous heterojunctions, which offer exceptional spatial resolution and finely tuned control over electrophysiological signals. These photoelectroceutical platforms are designed to deliver light-based modulation that can activate or suppress specific biological pathways with unprecedented precision. Beyond these fundamental advancements, we have demonstrated the practical utility of our platforms in a range of critical applications. For instance, our neuromodulation studies have shown promising results in modulating neural circuits, while our cardiac modulation experiments have paved the way for novel interventions in arrhythmia management. Additionally, we have developed several surgical delivery tools that integrate seamlessly with standard clinical procedures, thereby enhancing the efficacy and safety of implantable therapies. These accomplishments not only highlight the versatility of our approaches but also provide a robust foundation for future translational efforts in personalized medicine and regenerative therapies.
Looking ahead, our research agenda is dedicated to expanding the capabilities of implantable bioelectronic therapies, with a particular focus on advancing photoelectroceutical strategies. Our ultimate goal is to usher in a new era of implantable bioelectronic devices that not only advance human health and personalized therapies but also significantly enhance overall well-being, marking a critical step forward in medical technology innovation.

Keywords : Optoelectronic, Photoelectrochemical, Modulation, Implantable, Translational

Corresponding Author : Bozhi Tian (btian@uchicago.edu)

CV

Invited Speakers

15 XV. Next-Generation Electronic Materials and Devices beyond Moore’s Law

Keynote Speakers

Yutaka Wakayama

National Institute for Materials Science

Antiambipolar transistors for multifunctional electronic devices beyond von Neumann architecture

Abstract

Antiambipolar transistors for multifunctional electronic devices beyond von Neumann architecture

Yutaka Wakayama*1

1National Institute for Materials Science

In this talk, we will introduce an antiambipolar transistor (AAT) as a key element for multi-functional device architecture. The main component of the AAT is a pn-heterojunction formed around middle of the transistor channel. This unique device structure produces primordial and distinctive electrical properties, i.e., negative differential transconductance (NDT). The NDT can originate a variety of non-von Neumann type device operations.
We will introduce various applications of the ATTs, including multi-valued logic (MVL) circuits, reconfigurable two-input logic gates, logic-in-memory (LIM) and artificial synaptic devices. Ternary and quaternary logic states in the MVL circuits are advantageous to increase integration density beyond conventional binary systems. Reconfigurable logic gates, such as OR, NOR, AND or NAND circuits, can be operated just by a single dual-gate AAT. This is advantageous to simplify the design of the logic circuits. The logic-in-memory enables both data processing and storage in a single device by combining memory function with AATs for overcoming “von Neumann’s bottleneck”. Furthermore, both logic and memory states were multiplied at same time to realize a ternary LIM. Finally, preliminary study about the neuromorphic device will be presented as an example of the analogue devices for power-saving devices.
Firstly, we had carried out these studies by using organic semiconductors to open up a new frontier in organic electronics. Recently, we extended these device developments into two-dimensional atomic layers, such as h-BN and transition metal dichalcogenides (TMDCs) for beyond Moore’s law. At first, we will present organic AATs together with fundamental experiments to clarify the carrier transport mechanism, followed by latest device developments with TMDCs.

Keywords : pn-heterojunction, negative differential transconductance, multivalued logics, logic-in-memory, neuromorphics

Corresponding Author : Yutaka Wakayama (WAKAYAMA.Yutaka@nims.go.jp)

CV

Kyusang Lee

University of Virginia

CCMOS+X towards on-device AI

Abstract

CCMOS+X towards on-device AI

Kyusang Lee*1

1University of Virginia

Recent advances in heterogeneous integration and advanced packaging technology have enabled the combination of multiple functionalities into a single system. Among various, monolithic 3D integration of functional crystalline membranes, such as III-V, III-N, complex oxides and 2D materials has shown great potential to be integrated on both the front and back-sides of Si CMOS circuitry. The Integration of sensors, power delivery network and high bandwidth memory with CMOS computing units through 3D packaging technology attracts significant interest, especially for on-device AI applications. This advanced integration not only enhances computational capabilities but also opens up new possibilities in edge intelligence. Here, I will discuss how this cutting-edge technology revolutionizing edge intelligence, driving advancements in biomedical devices and robotics applications.

Keywords : in-sensor computing

Corresponding Author : Kyusang Lee (kyusang@virginia.edu)

CV

Invited Speakers