Hyungjin Lee
Daegu Gyeongbuk Institute of Science and Technology
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Publication
Featured researches published by Hyungjin Lee.
ACS Applied Materials & Interfaces | 2014
Yumi Ahn; Hyungjin Lee; Donghwa Lee; Youngu Lee
We successfully fabricated silver nanowire (AgNW)-based microelectrodes on various substrates such as a glass and polydimethylsiloxane by using a photolithographic process for the first time. The AgNW-based microelectrodes exhibited excellent electrical conductivity and mechanical flexibility. We also demonstrated the direct transfer process of AgNW-based microelectrodes from a glass to a biocompatible polyacrylamide-based hydrogel. The AgNW-based microelectrodes on the biocompatible hydrogel showed excellent electrical performance. Furthermore, they showed great mechanical flexibility as well as superior stability under wet conditions. We anticipate that the AgNW-based microelectrodes on biocompatible hydrogel substrates can be a promising platform for realization of practical bioelectronics devices.
ACS Nano | 2016
Zhaoyang Zhong; Hyungjin Lee; Dongwoo Kang; Sin Kwon; Young-Man Choi; Inhyuk Kim; Kwang Young Kim; Youngu Lee; Kyoohee Woo; Jooho Moon
Simple, low-cost and scalable patterning methods for Cu nanowire (NW)-based flexible transparent conducting electrodes (FTCEs) are essential for the widespread use of Cu NW FTCEs in numerous flexible optoelectronic devices, wearable devices, and electronic skins. In this paper, continuous patterning for Cu NW FTCEs via a combination of selective intense pulsed light (IPL) and roll-to-roll (R2R) wiping process was explored. The development of continuous R2R patterning could be achieved because there was significant difference in adhesion properties between NWs and substrates depending on whether Cu NW coated area was irradiated by IPL or not. Using a custom-built, R2R-based wiping apparatus, it was confirmed that nonirradiated NWs could be clearly removed out without any damage on irradiated NWs strongly adhered to the substrate, resulting in continuous production of low-cost Cu NW FTCE patterns. In addition, the variations in microscale pattern size by varying IPL process parameters/the mask aperture sizes were investigated, and possible factors affecting on developed pattern size were meticulously examined. Finally, the successful implementation of the patterned Cu NW FTCEs into a phosphorescent organic light-emitting diode (PhOLED) and a flexible transparent conductive heater (TCH) were demonstrated, verifying the applicability of the patterned FTCEs. It is believed that our study is the key step toward realizing the practical use of NW FTCEs in various flexible electronic devices.
Advanced Materials | 2016
Donghwa Lee; Hyungjin Lee; Youngjun Jeong; Yumi Ahn; Geonik Nam; Youngu Lee
Highly sensitive, transparent, and durable pressure sensors are fabricated using sea-urchin-shaped metal nanoparticles and insulating polyurethane elastomer. The pressure sensors exhibit outstanding sensitivity (2.46 kPa-1 ), superior optical transmittance (84.8% at 550 nm), fast response/relaxation time (30 ms), and excellent operational durability. In addition, the pressure sensors successfully detect minute movements of human muscles.
Journal of Materials Chemistry C | 2017
Yumi Ahn; Donghwa Lee; Youngjun Jeong; Hyungjin Lee; Youngu Lee
We prepared high performance metal nanowire (NW)-parylene C transparent electrodes (TEs) using pyrolytic deposition of a parylene C protection layer onto a silver nanowire (AgNW) or copper nanowire (CuNW) film at room temperature for the first time. The AgNW-parylene C TE showed superior optoelectronic properties such as high optical transmittance (94.7%) and low sheet resistance (41.6 Ω sq−1), comparable to a conventional indium tin oxide (ITO) TE. The AgNW-parylene C TE fabricated on a plastic substrate possessed outstanding flexibility. Moreover, the AgNW-parylene C and CuNW-parylene C TEs exhibited significantly improved oxidation and chemical stability due to the outstanding gas barrier properties of the parylene C protection layer. Furthermore, the potential suitability of the AgNW-parylene C TE was successfully demonstrated by fabricating flexible polymer solar cells. We expect that the flexible metal NW-parylene C TEs can be used as key elements for a variety of next generation optoelectronic devices.
Nanoscale | 2013
Donghwa Lee; Hyungjin Lee; Yumi Ahn; Youngjun Jeong; Dae-Young Lee; Youngu Lee
Carbon | 2015
Donghwa Lee; Hyungjin Lee; Yumi Ahn; Youngu Lee
Nanoscale | 2014
Hyungjin Lee; Donghwa Lee; Yumi Ahn; Eun-Woo Lee; Lee Soon Park; Youngu Lee
Chemistry of Materials | 2015
Honggi Kim; Hyungjin Lee; Donghyun Seo; Youngjun Jeong; Keun Cho; Jae-Chol Lee; Youngu Lee
Chemistry of Materials | 2017
Honggi Kim; Bogyu Lim; Hyojung Heo; Geonik Nam; Hyungjin Lee; Jiyoung Lee; Jae-Chol Lee; Youngu Lee
Synthetic Metals | 2016
Honggi Kim; Hyungjin Lee; Youngjun Jeong; Ju-Un Park; Donghyun Seo; Hyojung Heo; Donghwa Lee; Yumi Ahn; Youngu Lee