https://scholar.dgist.ac.kr/handle/20.500.11750/13619 2026-04-04T13:10:08Z https://scholar.dgist.ac.kr/handle/20.500.11750/60006 Title: Synergistic dual-electron acceptors in linear conjugated polymers for boosting photocatalytic hydrogen evolution Author(s): Kim, Sowon; Yu, Youngwoong; Choi, Hyunwoo; Ham, Gayoung; An, Sanghyeok; Lee, Soyeon; Yang, Jiwoong; Chung, Dae-sung; Lee, Jihoon; Cha, Hyojung Abstract: A conjugated polymer photocatalyst containing dual-electron acceptor units, dibenzo[b,d]thiophene sulfone (DBS) and 2,1,3-benzothiadiazole (BT), known as PBT, has been synthesized for its strong electron-withdrawing abilities and structural flexibility. However, the inherent hydrophobicity of PBT leads to significant particle aggregation, hindering colloidal stability and electron transfer to protons. To overcome these limitations, fluorine and ethylene glycol (EG) groups are strategically incorporated into the BT unit to enhance molecular planarity and hydrophilicity, respectively. This molecular engineering effectively suppresses exciton and charge recombination, facilitating efficient charge separation and extraction. Comprehensive spectroscopic analyses—including time-resolved photoluminescence (Tr-PL) and transient absorption spectroscopy (TAS)—reveal that EG-functionalized polymers exhibit prolonged exciton lifetimes and strong photoinduced absorption at early timescales, indicating both suppressed non-radiative recombination and effective charge generation. Importantly, these modifications enable rapid charge separation and transfer with more efficient electron extraction to protons, mitigating charge accumulation within aggregated domains. Among the modified polymers, 4EG-PBTz-F, with di-fluoro substituents and tetra-ethylene glycol groups, achieves the highest hydrogen evolution rates of 15.476 mmol g−1 and 3.095 mmol g−1 h−1 with a 3 wt% Pt co-catalyst. These results highlight the effectiveness of dual-electron acceptor design and interfacial control, offering a multi-faceted design strategy in photocatalytic hydrogen evolution systems. 2025-12-31T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/60005 Title: Graphene-Based Liquid Cell Designs for In Situ Liquid-Phase Transmission Electron Microscopy: Recent Developments and Perspectives Author(s): Ma, Hyeonjong; Kim, Hyeongseung; Yang, Jiwoong Abstract: Recent advances in liquid-phase transmission electron microscopy (TEM) have enabled the direct visualization of reaction pathways of nanomaterials, providing critical insights into diverse nanoscale processes such as crystallization, phase transition, shape transformation, etching, and nanoparticle motions. Among various liquid cells, graphene liquid cells (GLCs) are particularly advantageous due to the intrinsic properties of graphene—high electrical and thermal conductivity, exceptional mechanical flexibility, and radical scavenging effects—which allow atomic-scale spatial resolution and enhanced imaging stability. This review article highlights the recent progress in GLC-based liquid-phase TEM, focusing on the evolution of structural designs, including veil-type, well-type, liquid-flowing-type, and mixing-type GLCs. Each configuration offers unique advantages tailored to observing distinct types of nanoscale dynamic processes. These studies have elucidated both classical reaction pathways and complex, nonclassical mechanisms involving transient intermediates. Overall, this review highlights how developments in GLC designs have significantly advanced the capabilities of in situ liquid-phase TEM, providing unprecedented opportunities to study nanoscale processes at atomic resolution. 2025-11-30T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/59091 Title: Multifunctional electronic skin integrating dual-mode optical and pressure sensors for caregiving robots Author(s): Heo, Hyeonjun; Park, Jinhong; Ko, Daewon; Lee, Kyunghoon; Lee, Jinhee; Joo, Hyunwoo; Yang, Jiwoong; Cha, Gi Doo; Kim, Dae-Hyeong; Kim, Dong Chan Abstract: Advancements in artificial intelligence have broadened the capabilities of robots, particularly in caregiving applications that are essential for aging societies facing a growing shortage of human caregivers. Humanoid caregiving robots require sophisticated sensing systems to perform delicate tasks such as monitoring vital signs and providing physical assistance without causing discomfort. In particular, functionalities such as close-range proximity sensing, tactile feedback, and physiological and electrophysiological signal monitoring are essential for ensuring safe and effective caregiving. However, electronic skin (e-skin) capable of simultaneously detecting proximity, tactile, and physiological signals remains largely unexplored. Here, we present a multifunctional robotic e-skin that vertically integrates an optical sensor array and a pressure sensor array. The optical sensor, comprising quantum dot light-emitting diodes (QLEDs) and perovskite photodetectors (PDs), enables dual-mode sensing for both proximity detection and photoplethysmography (PPG) measurement. A carbon nanotube (CNT)-based pressure sensor array provides tactile feedback, ensuring stable and precise physiological monitoring. Additionally, the array structure allows cross-validation of proximity and PPG data, improving measurement accuracy and reliability. This multifunctional e-skin represents a significant advance toward the development of caregiving robots capable of safe, precise, and sophisticated human-robot interaction. 2025-09-30T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/58933 Title: Recent Progress on the Development of Intrinsically Stretchable Electroluminescent Devices Author(s): Kim, Dong Chan; Karl, Minji; Lee, Kyunghoon; Ko, Daewon; Kim, Dae-Hyeong; Yang, Jiwoong; Choi, Moon Kee Abstract: Intrinsically stretchable electroluminescent (is-EL) devices, whose components are made of mechanically soft and stretchable materials, are gaining significant attention as promising solutions for intrinsically stretchable displays. Compared to conventional stretchable devices with strain-distributing geometries, such as island-bridge or buckling structures, is-EL devices offer simpler device designs, enhanced mechanical reliability, and improved pixel density. This review highlights recent advancements in the development of is-EL devices, classifying them into two categories: alternating-current-driven electroluminescence devices (ACELs) and light-emitting diodes (LEDs). This work begins by exploring key materials for each component of is-EL devices, including electrodes, light-emitting layers, charge transport layers, and interconnections. This work also studies various device fabrication strategies for improving the luminous performance and pixel resolution. Then, this work discusses potential applications of is-EL devices, particularly focusing on wearable displays and multifunctional display technologies. Finally, this work concludes this review by commenting on the future outlook and unmet challenges. 2025-08-31T15:00:00Z