https://scholar.dgist.ac.kr/handle/20.500.11750/9972 2026-10-06T21:26:39Z 2026-10-06T21:26:39Z Ryu, Yeonkyeong Lee, Cheoljae Zhao, Pin Yeon, Jimin Choi, Jinsung Ibrahim, Tijani Okanlawon Gwak, Sujeong Gbadam, Gerald Selasie Moon, Yeongheum Shin, Dong-Myeong Lee, Ju Hun Lee, Ju-Hyuck https://scholar.dgist.ac.kr/handle/20.500.11750/60902 2026-09-29T05:40:15Z 2026-06-30T15:00:00Z

Title: Large-area kinetic stabilization of metastable R-glycine via meniscus-driven self-assembly with anisotropic piezoelectricity Author(s): Ryu, Yeonkyeong; Lee, Cheoljae; Zhao, Pin; Yeon, Jimin; Choi, Jinsung; Ibrahim, Tijani Okanlawon; Gwak, Sujeong; Gbadam, Gerald Selasie; Moon, Yeongheum; Shin, Dong-Myeong; Lee, Ju Hun; Lee, Ju-Hyuck Abstract: The development of natural piezoelectric biomaterials with tunable structure and functionality is crucial for advancing sustainable and biocompatible technologies in energy harvesting, implantable electronics, and biomedical systems. Glycine, the simplest amino acid classified into alpha, R, and gamma polymorphs, exhibits inherent substantial piezoelectricity at the R-phase structure. However, achieving controllable and scalable R-phase formation remains a key challenge due to its thermodynamic instability. Here, we present a scalable meniscus-guided self-assembly strategy for the large-area fabrication of uniform R-glycine crystals. Precise balancing of solvent evaporation and crystal growth kinetics enables direct crystallization and selective stabilization of the R-phase. This approach further induces pronounced crystallographic alignment, producing highly oriented R-glycine domains. The non-centrosymmetric structure and electromechanical functionality of the aligned crystals are verified by piezoresponse force microscopy (PFM) and second harmonic generation (SHG) analysis. The resulting assemblies demonstrate piezoelectric energy harvesting capability, confirming the potential of R-glycine as a functional piezoelectric material. This work offers a promising step toward enhancing the piezoelectric performance of natural biomaterials with potential implications for future self-powered biomedical applications.

2026-06-30T15:00:00Z Dong, Fuying Han, Chi Cai, Sheling T. Lee, Ju-Hyuck Niu, Simiao https://scholar.dgist.ac.kr/handle/20.500.11750/60423 2026-06-30T18:01:21Z 2025-11-30T15:00:00Z

Title: Skin-Integrated Wearable Electronics: A Dual-Interface Perspective Author(s): Dong, Fuying; Han, Chi; Cai, Sheling T.; Lee, Ju-Hyuck; Niu, Simiao Abstract: Skin-integrated wearable electronics enable continuous, medical-grade monitoring and therapy in daily life, but must balance conflicting needs related to mechanics, power, and communication. This review uses a dual-interface approach that separates the sensor–receiver interface, which handles wireless data and energy transfer, from the sensor–skin interface, where physiological signals are converted and mechanical and biological integration occur. We first reviewed wireless connections designed for skin electronics, focusing on Bluetooth Low Energy (BLE), Radio Frequency Identification (RFID)/Near-Field Communication (NFC) systems, and hybrid systems. Next, we examine sensor–skin interfaces ranging from mediated contact layers such as hydrogels for wearable ultrasound and soft conductive electrodes, to skin-conformal direct-contact methods based on structural mechanics, and ultrathin epidermal devices. Finally, we discuss cross-interface coupling, emphasizing how antenna layouts, power budgets, and body-induced RF effects limit mechanical design, and how skin mechanics influence link reliability. We conclude by exploring opportunities in battery-free and energy-autonomous systems, body-coupled communication, and integration with artificial intelligence (AI)-enabled digital health, positioning future electronic skins as soft, networked platforms that are comfortable and reliable. © 2026 The Author(s). SmartSys published by John Wiley & Sons Australia, Ltd on behalf of Youke Publishing Co., Ltd.

2025-11-30T15:00:00Z Park, Hyosik Gbadam, Gerald Selasie Lee, Cheoljae Joo, Hyeonseo Gwak, Sujeong Rojas, Orlando J. Lee, Ju-hyuck https://scholar.dgist.ac.kr/handle/20.500.11750/59987 2026-03-03T05:40:14Z 2026-01-31T15:00:00Z

Title: Dielectric Polarization-Driven Energy Amplification in 2D Nanostructure-Embedded PVC Gel TENGs for Tribo-Resistive Sensing Applications Author(s): Park, Hyosik; Gbadam, Gerald Selasie; Lee, Cheoljae; Joo, Hyeonseo; Gwak, Sujeong; Rojas, Orlando J.; Lee, Ju-hyuck Abstract: Plasticized poly(vinyl chloride) (PVC) gels are prototypical soft ionic polymers that combine strongly negative charge polarity with inherently high permittivity; however, their mobile ions impose substantial dielectric loss and leakage currents, which limit the output of triboelectric nanogenerators (TENGs). Here, graphene oxide (GO) nanosheets are embedded as 2D capacitive layers in a PVC gel, where they immobilize excess ions and add interfacial polarization, giving a dielectric constant of 32 at 1 kHz while lowering the dissipation factor (tan delta) by 65% relative to the pristine gel. The optimized GO-doped gel TENG delivers 282 V, 20.1 mu A, and 612 mu W/cm2-approximately 2.3, 2.0, and 2.5 times the values of the pristine PVC gel, respectively. A single GO-PVC gel layer simultaneously functions as both dielectric and electrode, powering a self-powered tribo-resistive sensor that pinpoints pressures up to 800 kPa over a 5 x 5 virtual grid, with a spatial resolution of approximate to 1.8 mm and pressure sensitivities of 194 mV/kPa (0-200 kPa) and 25 mV/kPa (200-800 kPa). By suppressing ion-driven loss while amplifying polarization, this 2D capacitive-layer strategy is transferable to other ionic-gel systems-including ionic-liquid gels and ionomers-charting a versatile route toward high-output soft TENGs for energy-autonomous wearables and electronic skin.

2026-01-31T15:00:00Z Kim, Dae-Hong Yu, Ju-Hyoung Lee, Cheoljae Seo, Min-Young Kim, Seungyeon Joo, Hyeonji Song, Young-Seok Bae, Sukang Lee, Ju-Hyuck Lee, Seoung-Ki Kim, Tae-Wook https://scholar.dgist.ac.kr/handle/20.500.11750/59359 2026-02-05T18:01:12Z 2025-12-31T15:00:00Z

Title: Reconfiguring Hierarchical Porous Architecture of 2D Metal Nanosheets for Multifunctional Triboelectric Nanogenerators Author(s): Kim, Dae-Hong; Yu, Ju-Hyoung; Lee, Cheoljae; Seo, Min-Young; Kim, Seungyeon; Joo, Hyeonji; Song, Young-Seok; Bae, Sukang; Lee, Ju-Hyuck; Lee, Seoung-Ki; Kim, Tae-Wook Abstract: 2D single-crystalline metal nanosheets are a promising platform for self-powered electronics, yet their potential for triboelectric nanogenerators (TENGs) remains unexplored. A key challenge in TENGs is overcoming low current output and limited durability. A hierarchical porous copper nanosheet-based TENG (HPC-TENG) is reported to substantially enhance triboelectric performance through a unique structural design. The method uses a simple spray-coating process to create a hierarchical porous conductive film from 2D copper nanosheets (Cu NSs). By infiltrating this film with polydimethylsiloxane (PDMS), interfacial contact is maximized, significantly boosting charge generation during mechanical cycling. The HPC-TENG achieves a remarkable 590% enhancement in electrical output compared to conventional Cu thin-film TENGs, while maintaining stable operation over 100 000 cycles. Beyond energy harvesting, this architecture provides integrated multifunctionality, including stable electromagnetic interference (EMI) shielding effectiveness exceeding 30 dB and efficient Joule heating. These findings highlight the strong potential of hierarchical porous metal nanosheet electrodes as a versatile platform for advanced energy harvesting, EMI shielding, and flexible heating, opening new avenues for next-generation wearable electronics.

2025-12-31T15:00:00Z