https://scholar.dgist.ac.kr/handle/20.500.11750/9972 Sat, 04 Apr 2026 12:47:56 GMT 2026-04-04T12:47:56Z https://scholar.dgist.ac.kr/handle/20.500.11750/59987 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. Sat, 31 Jan 2026 15:00:00 GMT https://scholar.dgist.ac.kr/handle/20.500.11750/59987 2026-01-31T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/59359 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. Wed, 31 Dec 2025 15:00:00 GMT https://scholar.dgist.ac.kr/handle/20.500.11750/59359 2025-12-31T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/59349 Title: Natural Antioxidant-Inspired Interfacial Engineering for Stable and High-Performance Perovskite Solar Cells Author(s): Choi, Seongmin; Yong, Taeyeong; Kim, Soo-Kwan; Park, Jin Young; Han, Sanghun; Seo, Gayoung; Kim, Hae Jeong; Ma, Hyeon Soo; Lee, Ju-Hyuck; Ko, Seo-Jin; Moon, Byung Joon; Choi, Jongmin Abstract: Although perovskite solar cells (PSCs) have recently achieved high certified power conversion efficiencies (PCEs), operational instability remains a critical obstacle to commercialization. In particular, superoxide (O2 center dot-) generated at metal-oxide charge-transport layers rapidly decomposes perovskites by deprotonating the organic cations (FA(+) and MA+) and therefore must be suppressed. Nevertheless, under operating illumination, the formation and diffusion of O2 center dot- are unavoidable as long as metal oxides are employed in PSCs. To address this, we introduce the natural antioxidant taurine at the SnO2/FAPbI3 interface to suppress O2 center dot- diffusion via chemical radical quenching. We elucidate the taurine-mediated O2 center dot- quenching mechanism through density functional theory (DFT) calculations supported by experiments. In addition, we find that I2 is concomitantly reduced to I- during the quenching process. This antioxidant interface prevents O2 center dot- induced perovskite decomposition under strongly oxidizing conditions. Moreover, the multifunctional groups of taurine form a chemical bridge between SnO2 and FAPbI3, reducing interfacial defect density, enhancing carrier mobility, and suppressing non-radiative recombination. Consequently, the taurine-buried interface enables an improved PCE with increased open-circuit voltage (VOC) and fill factor (FF), while markedly enhancing the light-soaking and operational stability of PSCs. https://scholar.dgist.ac.kr/handle/20.500.11750/59349 https://scholar.dgist.ac.kr/handle/20.500.11750/59230 Title: Mechanoluminescent-energy harvesting bimodal sensors for self-powered communication sensors Author(s): Hajra, Sugato; Panda, Swati; Kaja, Kushal Ruthvik; Song, Seongkyu; Ryu, Yeonkyeong; Panigrahi, Basanta Kumar; Vittayakorn, Naratip; Lee, Ju-Hyuck; Jeong, Soon Moon; Kim, Hoe Joon Abstract: Mechanoluminescence (ML) is the emission of light triggered by mechanical stress. In the meantime, accurate, quantitative force measurement is made possible by piezoelectricity, which transforms mechanical deformation into electrical signals. A deep insight into the mechanical interactions, such as strain-based phenomena, is achieved by integrating ML and piezoelectricity into a single device. In this study, a composite based on ZnS:Cu-polydimethylsiloxane (PDMS) is developed to achieve this dual functionality for ML-based optical responses and piezoelectric-based electrical output. The presence of piezoelectricity in PDMS-ZnS:Cu composites was traced using piezo force microscopy (PFM) imaging. Various mechanical stimuli of pressing, stretching, and bending are applied to evaluate the performance of the device. Under a force of 5 N, the piezoelectric nanogenerator (PENG) device generates a voltage of 17 V and a current of 70 nA. Additionally, ML and PENG effects are employed for underwater communications. A signal processing technique is further utilized for the classification of voltage signals produced during underwater communications. This self-powered dual-mode sensor has great potential for use in energy harvesting, wearable technology, and battery-free systems, opening the door to more intelligent and responsive user interfaces. Sun, 31 Aug 2025 15:00:00 GMT https://scholar.dgist.ac.kr/handle/20.500.11750/59230 2025-08-31T15:00:00Z