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Dive into the research topics where Chong Yun Kang is active.

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Featured researches published by Chong Yun Kang.


Advanced Materials | 2014

Highly Stretchable Piezoelectric‐Pyroelectric Hybrid Nanogenerator

Ju Hyuck Lee; Keun Young Lee; Manoj Kumar Gupta; Tae Yun Kim; Dae Yeong Lee; Junho Oh; Changkook Ryu; Won Jong Yoo; Chong Yun Kang; Seok Jin Yoon; Ji-Beom Yoo; Sang-Woo Kim

A highly stretchable hybrid nanogenerator has been developed using a micro-patterned piezoelectric polymer P(VDF-TrFE), PDMS-CNT composite, and graphene nanosheets. Mechanical and thermal energies are simultaneously harvested from a single cell of the device. The hybrid nanogenerator exhibits high robustness behavior even after 30% stretching and generates very stable piezoelectric and pyroelectric power outputs due to micro-pattern designing.


Scientific Reports | 2015

High Output Piezo/Triboelectric Hybrid Generator

Woo Suk Jung; Min Gyu Kang; Hi Gyu Moon; Seung Hyub Baek; Seok Jin Yoon; Zhong Lin Wang; Sang-Woo Kim; Chong Yun Kang

Recently, piezoelectric and triboelectric energy harvesting devices have been developed to convert mechanical energy into electrical energy. Especially, it is well known that triboelectric nanogenerators have a simple structure and a high output voltage. However, whereas nanostructures improve the output of triboelectric generators, its fabrication process is still complicated and unfavorable in term of the large scale and long-time durability of the device. Here, we demonstrate a hybrid generator which does not use nanostructure but generates much higher output power by a small mechanical force and integrates piezoelectric generator into triboelectric generator, derived from the simultaneous use of piezoelectric and triboelectric mechanisms in one press-and-release cycle. This hybrid generator combines high piezoelectric output current and triboelectric output voltage, which produces peak output voltage of ~370 V, current density of ~12 μA·cm−2, and average power density of ~4.44 mW·cm−2. The output power successfully lit up 600 LED bulbs by the application of a 0.2 N mechanical force and it charged a 10 μF capacitor to 10 V in 25 s. Beyond energy harvesting, this work will provide new opportunities for developing a small, built-in power source in self-powered electronics such as mobile electronics.


Advanced Materials | 2012

All‐Solution‐Processed Flexible Thin Film Piezoelectric Nanogenerator

Sung Yun Chung; Sunyoung Kim; Ju Hyuck Lee; Kyongjun Kim; Sang-Woo Kim; Chong Yun Kang; Seok Jin Yoon; Youn Sang Kim

An all-solution-processed flexible thin film piezoelectric nanogenerator is demonstrated using reactive zinc hydroxo-condensation and a screen-printing method. The highly elastic thin film allows the piezoelectric energy to be generated through the mechanical rolling and muscle stretching of the piezoelectric unit. This flexible all solution-processed nanogenerator is promising for use in future energy harvesters such as wearable human patches and mobile electronics.


Energy and Environmental Science | 2015

Mesoporous pores impregnated with Au nanoparticles as effective dielectrics for enhancing triboelectric nanogenerator performance in harsh environments

Jinsung Chun; Jin Woong Kim; Woo Suk Jung; Chong Yun Kang; Sang-Woo Kim; Zhong Lin Wang; Jeong Min Baik

A facile and scalable synthesis of mesoporous films impregnated with Au nanoparticles (NPs) as effective dielectrics is demonstrated for enhancing the nanogenerator performance based on vertical contact-separation mode. This technique is so simple and scalable, providing a promising solution for developing large-scale and practical self-powered devices. The spatial distribution of Au NPs made it possible to fabricate an Au NP-embedded mesoporous triboelectric nanogenerator (AMTENG) with a high output power of 13 mW under cycled compressive force, giving over 5-fold power enhancement, compared with a flat film-based TENG under the same mechanical force. It is proposed that the presence of aligned dipoles produced due to the charges created by the contact between Au NPs and PDMS inside the pores can influence the surface potential energy of mesoporous films. With such an enhanced power output and unique device design, we demonstrate various applications such as self-powered shape mapping sensors, foot-step driven large-scale AMTENGs, and integrated circuits with capacitors for powering commercial cell phones for realizing self-powered systems from footsteps, wind power, and ocean waves.


Nature Communications | 2016

Boosted output performance of triboelectric nanogenerator via electric double layer effect

Jinsung Chun; Byeong Uk Ye; Jae Won Lee; Dukhyun Choi; Chong Yun Kang; Sang-Woo Kim; Zhong Lin Wang; Jeong Min Baik

For existing triboelectric nanogenerators (TENGs), it is important to explore unique methods to further enhance the output power under realistic environments to speed up their commercialization. We report here a practical TENG composed of three layers, in which the key layer, an electric double layer, is inserted between a top layer, made of Al/polydimethylsiloxane, and a bottom layer, made of Al. The efficient charge separation in the middle layer, based on Voltas electrophorus, results from sequential contact configuration of the TENG and direct electrical connection of the middle layer to the earth. A sustainable and enhanced output performance of 1.22 mA and 46.8 mW cm−2 under low frequency of 3 Hz is produced, giving over 16-fold enhancement in output power and corresponding to energy conversion efficiency of 22.4%. Finally, a portable power-supplying system, which provides enough d.c. power for charging a smart watch or phone battery, is also successfully developed.


ACS Applied Materials & Interfaces | 2013

Extremely sensitive and selective NO probe based on villi-like WO3 nanostructures for application to exhaled breath analyzers.

Hi Gyu Moon; You Rim Choi; Young Seok Shim; Kwon Il Choi; Jong Heun Lee; Jin Sang Kim; Seok Jin Yoon; Hyung Ho Park; Chong Yun Kang; Ho Won Jang

Self-assembled WO3 thin film nanostructures with 1-dimensional villi-like nanofingers (VLNF) have been synthesized on the SiO2/Si substrate with Pt interdigitated electrodes using glancing angle deposition (GAD). Room-temperature deposition of WO3 by GAD resulted in anisotropic nanostructures with large aspect ratio and porosity having a relative surface area, which is about 32 times larger than that of a plain WO3 film. A WO3 VLNF sensor shows extremely high response to nitric oxide (NO) at 200 °C in 80% of relative humidity atmosphere, while responses of the sensor to ethanol, acetone, ammonia, and carbon monoxide are negligible. Such high sensitivity and selectivity to NO are attributed to the highly efficient modualtion of potential barriers at narrow necks between individual WO3 VLNF and the intrinsically high sensitivity of WO3 to NO. The theoretical detection limit of the sensor for NO is expected to be as low as 88 parts per trillion (ppt). Since NO is an approved biomarker of chronic airway inflammation in asthma, unprecedentedly high response and selectivity, and ppt-level detection limit to NO under highly humid environment demonstrate the great potential of the WO3 VLNF for use in high performance breath analyzers.


RSC Advances | 2013

Au-decorated WO3 cross-linked nanodomes for ultrahigh sensitive and selective sensing of NO2 and C2H5OH

Young-Seok Shim; Hi Gyu Moon; Do Hong Kim; Lihua Zhang; Seok-Jin Yoon; Young Soo Yoon; Chong Yun Kang; Ho Won Jang

Au-decorated WO3 cross-linked nanodomes are fabricated using soft templates composed of highly ordered polystyrene beads and self-agglomeration of Au. The distribution and size of Au nanoparticles on the surface of WO3 cross-linked nanodomes are controlled by varying the thickness of the initial Au film. The responses of Au-decorated WO3 cross-linked nanodomes to various gases such as NO2, CH3COCH3, C2H5OH, NH3, CO, H2, and C6H6 are at least 5 times higher than those of bare WO3 cross-linked nanodomes. The response enhancement by Au decoration is dependent on the target gas, which is attributed to an interplay between electronic and chemical sensitizations. In particular, the Au-decorated WO3 cross-linked nanodomes exhibit extremely high sensitivities and selectivities, and ppt-level detection limits to NO2 and C2H5OH at 250 °C and 450 °C, respectively. These results suggest that Au-decorated WO3 cross-linked nanodomes are very promising for use in breath analysers to diagnose both asthma and lung cancer from exhaled human breath.


Physical Chemistry Chemical Physics | 2014

A ferroelectric photocatalyst for enhancing hydrogen evolution: polarized particulate suspension

Sangbaek Park; Chan Woo Lee; Min Gyu Kang; Sanghyeon Kim; Hae Jin Kim; Ji Eon Kwon; Soo Young Park; Chong Yun Kang; Kug Sun Hong; Ki Tae Nam

A particle-based photocatalyst with a permanent internal field prepared by a corona poling method is presented as a novel approach to enhance the hydrogen evolution reaction in a particulate-suspension system. Photocatalytic activity of K0.5Na0.5NbO3 was significantly improved by 7.4 times after the polarization.


Applied Physics Letters | 2011

High-temperature thermoelectric properties of nanostructured Ca3Co4O9 thin films

Min Gyu Kang; Kwang Hwan Cho; Seung Min Oh; Jin Sang Kim; Chong Yun Kang; Sahn Nahm; Seok Jin Yoon

We prepared nanostructured Ca3Co4O9 (CCO) thin films by promoting localized epitaxial growth on polycrystalline Al2O3 substrates. The thermoelectric properties of the CCO films were studied in the temperature range 300 to 1023 K. We confirmed that localized epitaxial growth occurred on the seed grains that dominate the (006) plane. The nanostructured CCO thin films were found to have a maximum Seebeck coefficient of 206 μV/K and a power factor (at 920 K) of 0.514 mW/mK2. Moreover, the presence of nanostructure was found to reduce the thermal conductivity, and thus, should enhance the overall performance of CCO films in thermoelectric devices.


Journal of Materials Chemistry | 2014

Piezoelectric nanogenerators synthesized using KNbO3 nanowires with various crystal structures

Mi Ri Joung; Haibo Xu; In Tae Seo; Dae Hyeon Kim; Joon Hur; Sahn Nahm; Chong Yun Kang; Seok Jin Yoon; Hyun Min Park

KNbO3 (KN) nanowires having a tetragonal structure or a polymorphic phase boundary (PPB) structure, which contains both tetragonal (P4mm) and orthorhombic (Amm2) structures, are formed at low temperatures. The presence of tetragonal and PPB KN nanowires is attributed to the existence of OH− and H2O defects. Further, the tetragonal and PPB KN nanowires change to orthorhombic KN nanowires in the temperature range between 300 and 400 °C owing to desorption of the lattice hydroxyl group. A composite consisting of polydimethylsiloxane (PDMS) and KN nanowires having a PPB structure shows large dielectric constant and low dielectric loss values of 9.2 and 0.5%, respectively, at 100 kHz. Moreover, a nanogenerator (NG) synthesized using the PPB KN nanowires exhibits the largest output voltage and current among NGs synthesized using the tetragonal or orthorhombic KN nanowires. In particular, the NG containing 0.7 g of PPB KN nanowires shows an output voltage of 10.5 V and an output current of 1.3 μA; these values are among the highest ever reported for NGs synthesized using a lead-free composite. In addition, this NG exhibited the maximum output power and energy conversion efficiency, which were 4.5 μW and 0.9%, respectively, for an external load of 1.0 MΩ.

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Seok Jin Yoon

Korea Institute of Science and Technology

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Seok-Jin Yoon

Korea Institute of Science and Technology

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Ji-Won Choi

Korea Institute of Science and Technology

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Jin Sang Kim

Korea Institute of Science and Technology

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Seung Hyub Baek

Korea Institute of Science and Technology

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Hi Gyu Moon

Korea Institute of Science and Technology

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Ho Won Jang

Seoul National University

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Seong Keun Kim

Korea Institute of Science and Technology

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