Dr. Sung Bum Kang
@illinois.edu
Postdoctoral Research Associate, Braun Research Group
Materials Science and Engineering
University of Illinois
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
Baurzhan Salimzhanov, Jeoung Eun Kang, Navya Anna Raju, Sung Bum Kang, and Kyoung Jin Choi
Wiley
Stretchable photovoltaics have garnered increasing attention due to their adaptability to various surfaces and applications, meeting the rising demands for portable and flexible power sources. Herein, stretchable solar modules are demonstrated by sandwiching electrically connected rigid solar cells between top and bottom polydimethylsiloxane (PDMS) layers, which are then attached onto an elastomer with an island and trench structure. The electrical connection of solar cells is achieved by dispenser printing of electrically conductive adhesive (ECA). The fabricated stretchable solar modules have a maximum biaxial elongation of 75%, and the electrical connection of the solar cells using ECA results in a negligible efficiency loss of 1.6%. In particular, embedding of solar cells and interconnects between PDMS layers enhances mechanical stability by placing these key components at the mechanical neutral plane and the long‐term stability against humidity due to the encapsulation role of the PDMS layer. The module demonstrates only a 5% of efficiency drop after 1000 hours in the dump‐heat test (85°C/85%). The results in this study are not limited to solar cells but can be applied to various types of rigid devices, paving the way for the commercialization of stretchable electronics.
Sung Bum Kang, Guanglong Huang, Gaurav Singhal, Dajie Xie, Daniel H. Hsieh, Youngmun Lee, Ashish A. Kulkarni, John W. Smith, Qian Chen, Katsuyo Thornton,et al.
Wiley
AbstractTemplate‐directed self‐assembly of solidifying eutectics results in emergence of unique microstructures due to diffusion constraints and thermal gradients imposed by the template. Here, the importance of selecting the template material based on its conductivity to control heat transfer between the template and the solidifying eutectic, and thus the thermal gradients near the solidification front, is demonstrated. Simulations elucidate the relationship between the thermal properties of the eutectic and template and the resultant microstructure. The overarching finding is that templates with low thermal conductivities are generally advantageous for forming highly organized microstructures. When electrochemically porosified silicon pillars (thermal conductivity < 0.3 Wm−1K−1) are used as the template into which an AgCl‐KCl eutectic is solidified, 99% of the unit cells in the solidified structure exhibit the same pattern. In contrast, when higher thermal conductivity crystalline silicon pillars (≈100 Wm−1K−1) are utilized, the expected pattern is only present in 50% of the unit cells. The thermally engineered template results in mesostructures with tunable optical properties and reflectances nearly identical to the simulated reflectances of perfect structures, indicating highly ordered patterns are formed over large areas. This work highlights the importance of controlling heat flows in template‐directed self‐assembly of eutectics.
Anit Kumar Ambedkar, Durvesh Gautam, Manohar Singh, Sagar Vikal, Beer Pal Singh, Anil K. Malik, Sung Bum Kang, Ashwani Kumar, Amit Sanger, and Yogendra K. Gautam
Springer Science and Business Media LLC
Ashwani Kumar, Amit Sanger, Sung Bum Kang, and Ramesh Chandra
American Chemical Society (ACS)
In this report, we investigate the room-temperature gas sensing performance of heterostructure transition metal dichalcogenide (MoSe2/MoS2, WS2/MoS2, and WSe2/MoS2) thin films grown over a silicon substrate using a pulse laser deposition technique. The sensing response of the aforementioned sensors to a low concentration range of NO2, NH3, H2, CO, and H2S gases in air has been assessed at room temperature. The obtained results reveal that the heterojunctions of metal dichalcogenide show a drastic change in gas sensing performance compared to the monolayer thin films at room temperature. Nevertheless, the WSe2/MoS2-based sensor was found to have an excellent selectivity toward NO2 gas with a particularly high sensitivity of 10 ppb. The sensing behavior is explained on the basis of a change in electrical resistance as well as carrier localization prospects. Favorably, by developing a heterojunction of diselenide and disulfide nanomaterials, one may find a simple way of improving the sensing capabilities of gas sensors at room temperature.
Sung Bum Kang, Amit Sanger, Myeong Hoon Jeong, Jeong Min Baik, and Kyoung Jin Choi
Elsevier BV
Myeong Hoon Jeong, Sung Bum Kang, and Kyoung Jin Choi
American Chemical Society (ACS)
Sung Bum Kang, Rahul Sharma, Minhyeok Jo, Su In Kim, Jeongwoo Hwang, Sang Hyuk Won, Jae Cheol Shin, and Kyoung Jin Choi
MDPI AG
The growth of high-quality compound semiconductor materials on silicon substrates has long been studied to overcome the high price of compound semiconductor substrates. In this study, we successfully fabricated nanowire solar cells by utilizing high-quality hetero p-n junctions formed by growing n-type III-V nanowires on p-silicon substrates. The n-InAs0.75P0.25 nanowire array was grown by the Volmer–Weber mechanism, a three-dimensional island growth mode arising from a lattice mismatch between III-V and silicon. For the surface passivation of n-InAs0.75P0.25 core nanowires, a wide bandgap InP shell was formed. The nanowire solar cell was fabricated by benzocyclobutene (BCB) filling, exposure of nanowire tips by reactive-ion etching, electron-beam deposition of ITO window layer, and finally metal grid electrode process. In particular, the ITO window layer plays a key role in reducing light reflection as well as electrically connecting nanowires that are electrically separated from each other. The deposition angle was adjusted for conformal coating of ITO on the nanowire surface, and as a result, the lowest light reflectance and excellent electrical connectivity between the nanowires were confirmed at an oblique deposition angle of 40°. The solar cell based on the heterojunction between the n-InAs0.75P0.25/InP core-shell nanowire and p-Si exhibited a very high photoelectric conversion efficiency of 9.19% with a current density of 27.10 mA/cm2, an open-circuit voltage of 484 mV, and a fill factor of 70.1%.
Sung Bum Kang, Baurzhan Salimzhanov, Won Jin Park, Myeong Hoon Jeong, Ju‐Young Kim, and Kyoung Jin Choi
Wiley
Sung Bum Kang, Won Jin Park, Myeong Hoon Jeong, So‐Huei Kang, Changduk Yang, and Kyoung Jin Choi
Wiley
Ji-Hwan Kim, Sung Bum Kang, Hyeon-Hye Yu, Jaewon Kim, Jinhyeok Ryu, Ji-Won Lee, Kyoung Jin Choi, Chil-Min Kim, and Chang-Hwan Yi
The Optical Society
Vivek Vishal Sharma, Kyeong Nam Kim, Gi Hyeon Han, Eun‐Ji Gwak, Jeong‐Hyun Woo, Sung Bum Kang, Kyoung Jin Choi, Ju‐Young Kim, and Jeong Min Baik
Wiley
Sung Bum Kang, Ji-Hwan Kim, Myeong Hoon Jeong, Amit Sanger, Chan Ul Kim, Chil-Min Kim, and Kyoung Jin Choi
Springer Science and Business Media LLC
AbstractTransparent solar cells (TSCs) are emerging devices that combine the advantages of visible transparency and light-to-electricity conversion. Currently, existing TSCs are based predominantly on organics, dyes, and perovskites; however, the rigidity and color-tinted transparent nature of those devices strongly limit the utility of the resulting TSCs for real-world applications. Here, we demonstrate a flexible, color-neutral, and high-efficiency TSC based on a freestanding form of n-silicon microwires (SiMWs). Flat-tip SiMWs with controllable spacing are fabricated via deep-reactive ion etching and embedded in a freestanding transparent polymer matrix. The light transmittance can be tuned from ~10 to 55% by adjusting the spacing between the microwires. For TSCs, a heterojunction is formed with a p-type polymer in the top portion of the n-type flat-tip SiMWs. Ohmic contact with an indium-doped ZnO film occurs at the bottom, and the side surface has an Al2O3 passivation layer. Furthermore, slanted-tip SiMWs are developed by a novel solvent-assisted wet etching method to manipulate light absorption. Finite-difference time-domain simulation revealed that the reflected light from slanted-tip SiMWs helps light-matter interactions in adjacent microwires. The TSC based on the slanted-tip SiMWs demonstrates 8% efficiency at a visible transparency of 10% with flexibility. This efficiency is the highest among Si-based TSCs and comparable with that of state-of-the-art neutral-color TSCs based on organic–inorganic hybrid perovskite and organics. Moreover, unlike others, the stretchable and transparent platform in this study is promising for future TSCs.
Amit Sanger, Sung Bum Kang, Myeong Hoon Jeong, Chan Ul Kim, Jeong Min Baik, and Kyoung Jin Choi
American Chemical Society (ACS)
Transparent optoelectronics can enable a new class of applications such as transparent displays, smart windows, and invisible sensors. Here, we demonstrate all-transparent NO2 gas sensors based on ...
Amit Sanger, Sung Bum Kang, Myeong Hoon Jeong, Min Ji Im, In Young Choi, Chan Ul Kim, Hyungmin Lee, Yeong Min Kwon, Jeong Min Baik, Ho Won Jang,et al.
Wiley
Sung Bun Kang, Ki Chang Kwon, Kyoung Soon Choi, Rochelle Lee, Kootak Hong, Jun Min Suh, Min Ji Im, Amit Sanger, In Young Choi, Soo Young Kim,et al.
Elsevier BV
Myeong Hoon Jeong, Amit Sanger, Sung Bum Kang, Yeon Soo Jung, In Seon Oh, Jung Woo Yoo, Gun Ho Kim, and Kyoung Jin Choi
Royal Society of Chemistry (RSC)
PEG-treated poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) exhibited an enhanced power factor with increased strain.
Sung Bum Kang, Myeong Hoon Jeong, In Young Choi, So-Dam Sohn, Su Han Kim, Hyung-Joon Shin, Won Il Park, Jae Cheol Shin, Myoung Hoon Song, and Kyoung Jin Choi
Elsevier BV
Mi Gyoung Lee, Cheon Woo Moon, Hoonkee Park, Woonbae Sohn, Sung Bum Kang, Sanghan Lee, Kyoung Jin Choi, and Ho Won Jang
Wiley
Yeon Soo Jung, Dea Han Jeong, Sung Bum Kang, Fredrick Kim, Myeong Hoon Jeong, Ki-Suk Lee, Jae Sung Son, Jeong Min Baik, Jin-Sang Kim, and Kyoung Jin Choi
Elsevier BV
Sung Bum Kang, Sang Hyuk Won, Min Ji Im, Chan Ul Kim, Won Il Park, Jeong Min Baik, and Kyoung Jin Choi
IOP Publishing
Min Joo Park, Chan Ul Kim, Sung Bum Kang, Sang Hyuk Won, Joon Seop Kwak, Chil-Min Kim, and Kyoung Jin Choi
Wiley
Jiyoung Hwang, Dipali. S Patil, Sungbum Kang, Kyoung Jin Choi, and Jae Cheol Shin
American Scientific Publishers
Jeong Kwon, Min Ji Im, Chan Ul Kim, Sang Hyuk Won, Sung Bum Kang, Sung Ho Kang, In Taek Choi, Hwan Kyu Kim, In Ho Kim, Jong Hyeok Park,et al.
Royal Society of Chemistry (RSC)
A highly-efficient DSSC/Si monolithic tandem cell utilizing PEDOT:FTS as an interfacial catalytic layer.