https://scholar.dgist.ac.kr/handle/20.500.11750/1928 Thu, 11 Jun 2026 02:49:17 GMT 2026-06-11T02:49:17Z https://scholar.dgist.ac.kr/handle/20.500.11750/60361 Title: Transformation of rusted iron into an IDE-based sensor for ethanol detection and self-powered humidity sensing Author(s): Belal, Mohamed Ahmed; Hajra, Sugato; Bayoumy, Ahmed M.; Eldesouki, Mohammed H.; Kaja, Kushal Ruthvik; Panda, Swati; Ramu, Dandugudumula; Abd El-moneim, Ahmed; Achary, P. G. R.; Kim, Hoe Joon Abstract: Volatile organic compound (VOC) sensors and triboelectric nanogenerators (TENGs) are highly significant applications with broad potential across multiple fields, including non-invasive disease biomarker monitoring and sustainable energy harvesting for electronic devices. This study reports the synthesis of alpha-Fe2O3 nanoparticles derived from recycled iron screws using a closed-system nitric acid leaching process, followed by calcination, offering low-cost, eco-friendly, and added-value products that reduce the negative environmental impacts of waste materials. The synthesized material is thoroughly characterized to investigate its phase purity, surface morphology, and suitability for TENG and ethanolsensing applications. A spray coating technique was employed to deposit the alpha-Fe2O3 ink onto laserinduced graphene interdigitated electrodes (LIG-IDE) fabricated via CO2 laser engraving of a polyimide flexible substrate. The fabricated alpha-Fe2O3-based sensor exhibits multifunctional capabilities, owing to the material's biocompatibility. The alpha-Fe2O3-based sensor exhibits a high performance for ethanol detection at room temperature, with a sensor response of 47 and response/recovery times of 104/126 s, respectively, at 100 ppm. The TENG device exhibits stable output characteristics of 3 V and a maximum power of 9.5 nW. The electrical output from biomechanical motions confirms its potential for energy harvesting applications, and a further self-powered humidity sensor was demonstrated. These results highlight the excellent potential of alpha-Fe2O3 for both TENG applications and VOCs detection, recommending its use in environmental and industrial monitoring. Tue, 30 Jun 2026 15:00:00 GMT https://scholar.dgist.ac.kr/handle/20.500.11750/60361 2026-06-30T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/60232 Title: PDMS/BNT-BKT Composite-Based Triboelectric Nanogenerator for Self-Powered Health Monitoring Author(s): Sahu, Manisha; Hajra Sugato; Padhan, Aneeta Manjari; Park, Kyeong Jun; Hull, Anna Rose; Pakawanit, Phakkhananan; Keum, Hohyun; Kim, Hoe Joon Abstract: The field of sensors is moving toward miniaturization, and it requires suitable power sources for operation. In this context, the triboelectric nanogenerator (TENG) can become a partial solution as a sustainable power source for various sensors. The present work focuses on developing a TENG fabricated from the flexible polymer-ceramic composite films, i.e., PDMS-Bi0.5(Na1-x K x )0.5TiO3 where x = 0.1, 0.14, 0.18, and 0.22 (BNT-BKT), which act as potential self-powering devices for sleep and respiration monitoring. The structural and spectroscopic characterization of the BNT-BKT particles showcased the presence of a morphotropic phase boundary. The dielectric constant increases with the inclusion of BKT, and the observed dielectric loss of the BNT-BKT samples is much less compared to that of the parent BNT samples. An attempt is made to fabricate a TENG based on PDMS/BNT-BKT composites (CFs). The triboelectric nanogenerator with 10 wt % PDMS/BNT-BKT CF gives an electrical output voltage of 292 V and a current of 3.47 mu A. Finally, a calculator is successfully powered by charging a 47 mu F capacitor using the fabricated TENG device. Furthermore, the TENG device is utilized for continuous monitoring of breathing patterns during rapid exercise and also jerks during sleep, underscoring its wide application in healthcare monitoring. Wed, 31 Dec 2025 15:00:00 GMT https://scholar.dgist.ac.kr/handle/20.500.11750/60232 2025-12-31T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/60227 Title: Toward virtual bladder: real-time bladder volume monitoring with flexible AuCNT strain sensors Author(s): Cho, Youngjun; Jo, Yujin; Kang, Minseok; Shin, Heejae; Cho Jeongmok; Jeong Hyunghwa; Suh Hyunsuk Peter; Pak Changsik John; Park, Jeonhyeong; Kwon Soonchul; Choi Hongsoo; Yu, Jaesok; Kim, Hoe Joon; Lee, Sanghoon Abstract: Digital twin technology holds considerable potential for personalized diagnostics and treatment of bladder dysfunction, particularly neurogenic conditions such as underactive bladder (UAB). In this study, to address the need for precise monitoring, we introduce a flexible, stretchable strain sensor composed of gold-coated carbon nanotubes (AuCNTs) embedded in Ecoflex. We specifically designed a three-channel configuration to capture anisotropic expansion and evaluated the sensor's performance using both two-dimensional balloon models and ex-vivo three-dimensional porcine bladder models. As a result, the AuCNT sensor demonstrated high sensitivity, and the three-channel design significantly enhanced spatial accuracy compared to single-channel approaches. Based on these measurements, we created a preliminary "Virtual Bladder" model that provides dynamic, real-time visualization of bladder volume changes. While our current model requires further development to incorporate multimodal data and anatomical variability, it serves as a foundational step towards developing advanced digital twin frameworks and closed-loop neuromodulation systems for bladder dysfunction. Wed, 31 Dec 2025 15:00:00 GMT https://scholar.dgist.ac.kr/handle/20.500.11750/60227 2025-12-31T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/59344 Title: Triboelectric self-powered soft robotics: paving the way towards a sustainable future Author(s): Srujan Kumar, Arraboina; Avinash, Borem; Rao, Mamidi Yugandhar; Boominathan, Jananipriya; Hajra, Sugato; Panda, Swati; Kim, Hoe Joon; Manojkumar, Kaliyannan; Vivekananthan, Venkateswaran Abstract: The integration of triboelectric nanogenerators (TENGs) into soft robotic systems marks a significant advancement toward autonomous, self-powered, and environmentally responsive machines. TENGs offer lightweight, flexible structures capable of efficiently converting mechanical energy into electricity, supporting both on-board power generation and active sensing. This review provides a comprehensive overview of recent progress in TENG-powered soft robotics, emphasizing developments in actuation, sensing, locomotion, and intelligent interaction. Notable systems include freestanding-mode TENG-Bots, tribo-piezoelectric soft grippers, somatosensory fingers, light-responsive actuators, and electrohydrodynamic pumps each demonstrating TENGs' dual role as energy sources and control elements. Bioinspired designs, such as leech-like and star-nosed mole-inspired robots, further illustrate their potential in adaptive locomotion and nonvisual spatial perception. The integration of TENGs with soft materials and intelligent feedback architectures enables untethered, multifunctional robotic platforms with applications ranging from wearable electronics and human-machine interfaces to environmental exploration. This review also discusses current limitations, including low energy output, durability challenges, and system-level integration, while outlining future research directions in material optimization, energy storage, wireless control, and machine learning-enhanced perception. Collectively, these developments underscore the transformative impact of TENGs on the future of intelligent soft robotics. Fri, 31 Oct 2025 15:00:00 GMT https://scholar.dgist.ac.kr/handle/20.500.11750/59344 2025-10-31T15:00:00Z