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22 results on '"Han, Se Gyo"'

6. Fluorination-Induced Conversion of the Quasi- to the Normal Interchain Packing in Push–Pull Conjugated Polymer Aggregates

Author

Yun, Hyuk Gu, primary, Nho, Hak-Won, additional, Han, Se Gyo, additional, Cho, Jun Sang, additional, Bang, Jieun, additional, Yoon, Tae Woong, additional, Mun, Jungho, additional, Noh, Jaebum, additional, Jeong, Minyoung, additional, Kim, Dong Hyeon, additional, Kim, Bora, additional, Hwang, Hyeongjin, additional, Jeong, Mun Seok, additional, Lee, Hansol, additional, Rho, Junsuk, additional, Kang, Boseok, additional, Park, JaeHong, additional, Jang, Joon I., additional, Cho, Kilwon, additional, Kwon, Oh-Hoon, additional, and Lee, Dongki, additional

Published
2023
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9. Elucidating the Chain-Extension Effect on the Exciton-Dissociation Mechanism through an Intra- or Interchain Polaron-Pair State in Push–Pull Conjugated Polymers

Author

Lee, Dongki, primary, Han, Se Gyo, additional, Kim, Hyojung, additional, Hwang, Hyeongjin, additional, Park, Chaneui, additional, Noh, Jaebum, additional, Mun, Jungho, additional, Nho, Hak-Won, additional, Cho, Jeong Bin, additional, Kim, Dong Hyeon, additional, Jeong, Byeong Geun, additional, Oh, Chang-Mok, additional, Yoon, Taewoong, additional, Sung, Woong, additional, Lee, Hansol, additional, Nah, Sanghee, additional, Kang, Boseok, additional, Hwang, In-Wook, additional, Jang, Joon I., additional, Kwon, Oh-Hoon, additional, Rho, Junsuk, additional, Jeong, Mun Seok, additional, and Cho, Kilwon, additional

Published
2022
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10. Photomultiplication‐Type Organic Photodetectors with High EQE‐Bandwidth Product by Introducing a Perovskite Quantum Dot Interlayer.

Author

Jeong, Minyoung, Han, Se Gyo, Sung, Woong, Kim, Seunghyun, Min, Jiwoo, Kim, Mi Kyong, Choi, Wookjin, Lee, Hansol, Lee, Dongki, Kim, Min, and Cho, Kilwon

Subjects
*PHOTODETECTORS, *PEROVSKITE, *QUANTUM efficiency, *QUANTUM dots, *ANIONS, *ELECTRODES
Abstract

A photomultiplication (PM)‐type organic photodetector (OPD) that exploits the ionic motion in CsPbI3 perovskite quantum dots (QDs) is demonstrated. The device uses a QD monolayer as a PM‐inducing interlayer and a donor–acceptor bulk heterojunction (BHJ) layer as a photoactive layer. When the device is illuminated, negative ions in the CsPbI3 QD migrate and accumulate near the interface between the QDs and the electrode; these processes induce hole injection from the electrode and yield the PM phenomenon with an external quantum efficiency (EQE) >2000% at a 3 V applied bias. It is confirmed that the ionic motion of the CsPbI3 QDs can induce a shift in the work function of the QD/electrode interface and that the dynamics of ionic motion determines the response speed of the device. The PM OPD showed a large EQE‐bandwidth product >106 Hz with a −3 dB frequency of 125 kHz at 3 V, which is one of the highest response speeds reported for a PM OPD. The PM‐inducing strategy that exploits ionic motion of the interlayer is a potential approach to achieving high‐efficiency PM OPDs. [ABSTRACT FROM AUTHOR]

Published
2023
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12. Nanomorphology dependence of the environmental stability of organic solar cells

Author

50301239, Sung, Woong, Lee, Hansol, Choi, Wookjin, Han, Se Gyo, Kim, Jimin, Cho, Kwangwoo, Kim, Seung Hyun, Lee, Dongki, Kim, Hyung Do, Ohkita, Hideo, Cho, Kilwon, 50301239, Sung, Woong, Lee, Hansol, Choi, Wookjin, Han, Se Gyo, Kim, Jimin, Cho, Kwangwoo, Kim, Seung Hyun, Lee, Dongki, Kim, Hyung Do, Ohkita, Hideo, and Cho, Kilwon

Abstract

Previous studies have reported contradictory effects of small-molecule acceptors on the environmental stability of polymer:small-molecule blends, with one showing that a small-molecule acceptor stabilizes and another showing that it destabilizes the polymer donor. In this work, to investigate the origin of these contradictory results, the effects of the nanomorphologies of small-molecule acceptors on the environmental stability of polymer:small-molecule blends are demonstrated. Investigations on the environmental stabilities of polymer:fullerene blends of poly[[4, 8-bis[(2-ethylhexyl)oxy]benzo[1, 2-b:4, 5-b′]dithiophene-2, 6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3, 4-b]thiophenediyl]] (PTB7):phenyl-C₆₁-butyric acid methyl ester (PCBM) with contrasting nanomorphologies of PCBM reveal that dispersed PCBM in a mixed phase is the critical factor that causes triplet-mediated singlet oxygen generation and, hence, the severe photooxidation of PTB7, whereas an aggregated PCBM phase stabilizes PTB7 by reducing the formation of PTB7 triplet excitons. In addition, the photooxidation of PTB7 substantially degrades hole transport in the PTB7:PCBM blends by destroying the crystalline PTB7 phases within the films; this effect is strongly correlated with the efficiency losses of the PTB7:PCBM organic solar cells. These conclusions are also extended to polymer:nonfullerene blends of PTB7:ITIC and PTB7:Y6, thereby confirming the generality of this phenomenon for polymer:small-molecule organic solar cells.

Published
2022

13. Intrachain Delocalization Effect of Charge Carriers on the Charge-Transfer State Dynamics in Organic Solar Cells

Author

Lee, Dongki, primary, Lee, Jaewon, additional, Sin, Dong Hun, additional, Han, Se Gyo, additional, Lee, Hansol, additional, Choi, Wookjin, additional, Kim, Hyojung, additional, Noh, Jaebum, additional, Mun, Jungho, additional, Sung, Woong, additional, Kim, Sang Woo, additional, Jeong, Byeong Geun, additional, Kim, Sung Hyuk, additional, Rho, Junsuk, additional, Jeong, Mun Seok, additional, and Cho, Kilwon, additional

Published
2022
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17. Charge Recycling Mechanism Through a Triplet Charge-Transfer State in Ternary-Blend Organic Solar Cells Containing a Nonfullerene Acceptor

Author

Lee, Dongki, primary, Hwang, Hyeongjin, additional, Sin, Dong Hun, additional, Park, Chaneui, additional, Han, Se Gyo, additional, Mun, Jungho, additional, Noh, Jaebum, additional, Kim, Sung Hyuk, additional, Kim, Hyojung, additional, Lee, Hansol, additional, Lee, Chanwoo, additional, Rho, Junsuk, additional, Cho, Kilwon, additional, and Jeong, Mun Seok, additional

Published
2021
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20. Position‐Induced Efficient Doping for Highly Doped Organic Thermoelectric Materials.

Author

Min, Jiwoo, Kim, Daegun, Han, Se Gyo, Park, Chaneui, Lim, Hyungsub, Sung, Woong, and Cho, Kilwon

Subjects
SEMICONDUCTOR doping, ORGANIC semiconductors, ELECTRIC conductivity, SEEBECK coefficient, THERMOELECTRIC materials, THIOPHENES, CONDUCTING polymers
Abstract

Electrical doping is essentially required for high‐performance organic thermoelectric (TE) materials; however, the doping efficiency ηd has not been extensively investigated in highly doped organic semiconductors (OSCs). Here, it is demonstrated that the distribution of dopant molecules in a specific position in highly doped OSCs affects the ηd, which is critically related to the Seebeck coefficient S and the electrical conductivity σ. Poly(2,5‐bis(3‐hexadecylthiophen‐2‐yl)thieno[3,2‐b]thiophene) (PBTTT) films are p‐doped with 2,3,5,6‐tetrafluoro‐7,7,8,8‐tetracyanoquinodimethane (F4TCNQ) by either solution‐sequential (SSq) doping or vapor doping. SSq doping deposited F4TCNQ only in the amorphous domains of PBTTT films, whereas vapor doping deposited it in both the amorphous and crystalline domains. F4TCNQ molecules in the crystalline domains exhibited a high ηd and led to a rapid increase of the power factor with increasing σ: S2σ ∝ σ0.76. These results provide guidance for the efficient doping of highly doped OSCs and emphasize the importance of doping efficiency in obtaining high‐performance organic TE materials. [ABSTRACT FROM AUTHOR]

Published
2022
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