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8. Impact of Optimized Operations for Binary Field Inversion on Quantum Computers

Author

Jang, Kyoungbae, Choi, Seung Ju, Kwon, Hyeokdong, Hu, Zhi, Seo, Hwajeong, Goos, Gerhard, Founding Editor, Hartmanis, Juris, Founding Editor, Bertino, Elisa, Editorial Board Member, Gao, Wen, Editorial Board Member, Steffen, Bernhard, Editorial Board Member, Woeginger, Gerhard, Editorial Board Member, Yung, Moti, Editorial Board Member, and You, Ilsun, editor

Published
2020
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9. Compact Implementation of CHAM Block Cipher on Low-End Microcontrollers

Author

Kwon, Hyeokdong, Kim, Hyunji, Choi, Seung Ju, Jang, Kyoungbae, Park, Jaehoon, Kim, Hyunjun, Seo, Hwajeong, Goos, Gerhard, Founding Editor, Hartmanis, Juris, Founding Editor, Bertino, Elisa, Editorial Board Member, Gao, Wen, Editorial Board Member, Steffen, Bernhard, Editorial Board Member, Woeginger, Gerhard, Editorial Board Member, Yung, Moti, Editorial Board Member, and You, Ilsun, editor

Published
2020
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10. Detecting Block Cipher Encryption for Defense Against Crypto Ransomware on Low-End Internet of Things

Author

Kim, Hyunji, Park, Jaehoon, Kwon, Hyeokdong, Jang, Kyoungbae, Choi, Seung Ju, Seo, Hwajeong, Goos, Gerhard, Founding Editor, Hartmanis, Juris, Founding Editor, Bertino, Elisa, Editorial Board Member, Gao, Wen, Editorial Board Member, Steffen, Bernhard, Editorial Board Member, Woeginger, Gerhard, Editorial Board Member, Yung, Moti, Editorial Board Member, and You, Ilsun, editor

Published
2020
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12. Pseudo-halide anion engineering for α-FAPbI3 perovskite solar cells

Author

Jeong, Jaeki, Kim, Minjin, Seo, Jongdeuk, Lu, Haizhou, Ahlawat, Paramvir, Mishra, Aditya, Yang, Yingguo, Hope, Michael A., Eickemeyer, Felix T., Kim, Maengsuk, Yoon, Yung Jin, Choi, In Woo, Darwich, Barbara Primera, Choi, Seung Ju, Jo, Yimhyun, Lee, Jun Hee, Walker, Bright, Zakeeruddin, Shaik M., Emsley, Lyndon, Rothlisberger, Ursula, Hagfeldt, Anders, Kim, Dong Suk, Grätzel, Michael, and Kim, Jin Young

Published
2021
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17. Liquid‐State Dithiocarbonate‐Based Polymeric Additives with Monodispersity Rendering Perovskite Solar Cells with Exceptionally High Certified Photocurrent and Fill Factor

Author

Kim, Kyusun, primary, Han, Jiye, additional, Lee, Sangsu, additional, Kim, Soyeon, additional, Choi, Jin‐Myung, additional, Nam, Jeong‐Seok, additional, Kim, Dawoon, additional, Chung, In, additional, Kim, Tae‐Dong, additional, Manzhos, Sergei, additional, Choi, Seung Ju, additional, Song, Ji Won, additional, Kim, Dong Suk, additional, Do, Jung Yun, additional, and Jeon, Il, additional

Published
2023
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19. Perovskite solar cells approaching 25% PCE using side chain terminated hole transport materials with low concentration in a non-halogenated solvent process

Author

Xie, Zhiqing, primary, Do, Yeongju, additional, Choi, Seung Ju, additional, Park, Ho-Yeol, additional, Kim, Hyerin, additional, Kim, Jeonghyeon, additional, Song, Donghyun, additional, Gokulnath, Thavamani, additional, Kim, Hak-Beom, additional, Choi, In Woo, additional, Jo, Yimhyun, additional, Kim, Dong Suk, additional, Yoon, Seog-Young, additional, Cho, Young-Rae, additional, and Jin, Sung-Ho, additional

Published
2023
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20. Formate as Anti‐Oxidation Additives for Pb‐Free FASnI 3 Perovskite Solar Cells

Author

Jang, Hyungsu, primary, Lim, Hyeong Yong, additional, Yoon, Yung Jin, additional, Seo, Jongdeuk, additional, Park, Chan Beom, additional, Son, Jung Geon, additional, Kim, Jae Won, additional, Shin, Yun Seop, additional, An, Na Gyeong, additional, Choi, Seung Ju, additional, Kim, Su Hwan, additional, Jeong, Jaeki, additional, Jo, Yimhyun, additional, Kwak, Sang Kyu, additional, Kim, Dong Suk, additional, and Kim, Jin Young, additional

Published
2022
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21. Conformal quantum dot-SnO2 layers as electron transporters for efficient perovskite solar cells

Author

Kim, Minjin, Jeong, Jaeki, Lu, Haizhou, Lee, Tae Kyung, Eickemeyer, Felix T., Liu, Yuhang, Choi, In Woo, Choi, Seung Ju, Jo, Yimhyun, Kim, Hak-Beom, Mo, Sung-In, Kim, Young-Ki, Lee, Heunjeong, An, Na Gyeong, Cho, Shinuk, Tress, Wolfgang R., Zakeeruddin, Shaik M., Hagfeldt, Anders, Kim, Jin Young, Grätzel, Michael, Kim, Dong Suk, Kim, Minjin, Jeong, Jaeki, Lu, Haizhou, Lee, Tae Kyung, Eickemeyer, Felix T., Liu, Yuhang, Choi, In Woo, Choi, Seung Ju, Jo, Yimhyun, Kim, Hak-Beom, Mo, Sung-In, Kim, Young-Ki, Lee, Heunjeong, An, Na Gyeong, Cho, Shinuk, Tress, Wolfgang R., Zakeeruddin, Shaik M., Hagfeldt, Anders, Kim, Jin Young, Grätzel, Michael, and Kim, Dong Suk

Abstract

Improvements to perovskite solar cells (PSCs) have focused on increasing their power conversion efficiency (PCE) and operational stability and maintaining high performance upon scale-up to module sizes. We report that replacing the commonly used mesoporous-titanium dioxide electron transport layer (ETL) with a thin layer of polyacrylic acid-stabilized tin(IV) oxide quantum dots (paa-QD-SnO2) on the compact-titanium dioxide enhanced light capture and largely suppressed nonradiative recombination at the ETL-perovskite interface. The use of paa-QD-SnO2 as electron-selective contact enabled PSCs (0.08 square centimeters) with a PCE of 25.7% (certified 25.4%) and high operational stability and facilitated the scale-up of the PSCs to larger areas. PCEs of 23.3, 21.7, and 20.6% were achieved for PSCs with active areas of 1, 20, and 64 square centimeters, respectively.

Published
2022

22. Conformal quantum dot–SnO 2 layers as electron transporters for efficient perovskite solar cells

Author

Kim, Minjin, primary, Jeong, Jaeki, additional, Lu, Haizhou, additional, Lee, Tae Kyung, additional, Eickemeyer, Felix T., additional, Liu, Yuhang, additional, Choi, In Woo, additional, Choi, Seung Ju, additional, Jo, Yimhyun, additional, Kim, Hak-Beom, additional, Mo, Sung-In, additional, Kim, Young-Ki, additional, Lee, Heunjeong, additional, An, Na Gyeong, additional, Cho, Shinuk, additional, Tress, Wolfgang R., additional, Zakeeruddin, Shaik M., additional, Hagfeldt, Anders, additional, Kim, Jin Young, additional, Grätzel, Michael, additional, and Kim, Dong Suk, additional

Published
2022
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23. Formate as Anti‐Oxidation Additives for Pb‐Free FASnI3 Perovskite Solar Cells.

Author

Jang, Hyungsu, Lim, Hyeong Yong, Yoon, Yung Jin, Seo, Jongdeuk, Park, Chan Beom, Son, Jung Geon, Kim, Jae Won, Shin, Yun Seop, An, Na Gyeong, Choi, Seung Ju, Kim, Su Hwan, Jeong, Jaeki, Jo, Yimhyun, Kwak, Sang Kyu, Kim, Dong Suk, and Kim, Jin Young

Subjects
SOLAR cells, PEROVSKITE, OPEN-circuit voltage, CHEMICAL stability, DENSITY functional theory, OXIDATIVE addition, CARRIER density
Abstract

Pb‐free Sn‐based perovskite solar cells (PSCs) have significant potential for application in photovoltaic devices because of their suitable bandgap, low exciton binding energy, high carrier mobility, and long diffusion length. However, their performance is hampered by several issues. Sn‐based perovskites are highly susceptible to oxidation, which induces a high concentration of defects and degrades the chemical stability of the perovskite crystals. Herein, the anion formate (HCOO−) can effectively suppress the oxidation of Sn in the pure formamidinium tin triiodide (FASnI3) perovskite without using A‐site cationic additives. Moreover, the presence of formate results in a uniform pinhole‐free perovskite film with a low trap density, reduced charge carrier recombination, and improved charge extraction. Density functional theory calculations show that formate‐treated FASnI3 has improved stability against oxidative Sn degradation. The formate‐treated PSC achieves a power conversion efficiency of 12.11% at a high open‐circuit voltage of 0.71 V. The device exhibits improved stability in ambient air in which it maintained over 80% of its initial power conversion efficiency after 180 min because oxidation is inhibited owing to the strong interaction between Sn and formate. [ABSTRACT FROM AUTHOR]

Published
2022
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28. Enhanced electrical properties of Li-salts doped mesoporous TiO2in perovskite solar cells

Author

Kim, Minjin, Choi, In-woo, Choi, Seung Ju, Song, Ji Won, Mo, Sung-In, An, Jeong-Ho, Jo, Yimhyun, Ahn, SeJin, Ahn, Seoung Kyu, Kim, Gi-Hwan, and Kim, Dong Suk

Abstract

The charge transferability of the electron transfer layers (ETLs) is important for achieving high performance in mesoscopic (mp) perovskite solar cells (PSCs). However, because of the low electron extraction efficiency of TiO2, lithium doping is essentially required. In this work, we compared the electrical properties of mp-TiO2doped with Li-salts with different anions—LiTFSI, Li2CO3, LiCl, and LiF. Interestingly, we found that the anions of the Li-salt dopants affect the electrical properties of the ETLs and the solar cell performance. The Li2CO3doping of mp-TiO2led to conduction bands deeper than those of pristine mp-TiO2or other doped mp-TiO2. The maximum efficiency of 25.28% and certified efficiency of 24.68% (Newport) was obtained by using Li2CO3dopant. This optimization of the ETLs properties is expected to greatly contribute to the progress of PSCs by leading to further increases in their efficiency.

Published
2021
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29. Pseudo-halide anion engineering for α-FAPbI3perovskite solar cells

Author

Jeong, Jaeki, Kim, Minjin, Seo, Jongdeuk, Lu, Haizhou, Ahlawat, Paramvir, Mishra, Aditya, Yang, Yingguo, Hope, Michael A., Eickemeyer, Felix T., Kim, Maengsuk, Yoon, Yung Jin, Choi, In Woo, Darwich, Barbara Primera, Choi, Seung Ju, Jo, Yimhyun, Lee, Jun Hee, Walker, Bright, Zakeeruddin, Shaik M., Emsley, Lyndon, Rothlisberger, Ursula, Hagfeldt, Anders, Kim, Dong Suk, Grätzel, Michael, and Kim, Jin Young

Abstract

Metal halide perovskites of the general formula ABX3—where A is a monovalent cation such as caesium, methylammonium or formamidinium; B is divalent lead, tin or germanium; and X is a halide anion—have shown great potential as light harvesters for thin-film photovoltaics1–5. Among a large number of compositions investigated, the cubic α-phase of formamidinium lead triiodide (FAPbI3) has emerged as the most promising semiconductor for highly efficient and stable perovskite solar cells6–9, and maximizing the performance of this material in such devices is of vital importance for the perovskite research community. Here we introduce an anion engineering concept that uses the pseudo-halide anion formate (HCOO−) to suppress anion-vacancy defects that are present at grain boundaries and at the surface of the perovskite films and to augment the crystallinity of the films. The resulting solar cell devices attain a power conversion efficiency of 25.6 per cent (certified 25.2 per cent), have long-term operational stability (450 hours) and show intense electroluminescence with external quantum efficiencies of more than 10 per cent. Our findings provide a direct route to eliminate the most abundant and deleterious lattice defects present in metal halide perovskites, providing a facile access to solution-processable films with improved optoelectronic performance.

Published
2021
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33. AMLCD glass mirror constant and crack flaw size in non-crack LCD panels.

Author

Kim, Si-jin and Choi, Seung-ju

Subjects
CRACK initiation (Fracture mechanics), LIQUID crystal displays, GLASS, ACTIVE-matrix liquid crystal displays, ELECTRONICS manufacturing
Abstract

Portable models based on the latest liquid crystal displays (LCDs) have been useful in various areas. Many developers have pursued thinner hardware as well as the advanced performance of portable models. Therefore, as the panel glass continuously becomes thinner, the strength characteristics of glass are highlighted as an important issue. In particular, the strength of the LCD glass is mentioned as an important issue. The occurrence of surface scratches on the active-matrix liquid crystal display glass substrates should be minimized to produce portable models with stability; if their crack flaw sizes are kept below a certain level or close to zero, strength-differentiated LCD panel production will be possible. This study confirmed that in LCD panels where the thin-film transistor-color filter (TFT-CF) is assembled, cracks are generated mainly in the TFT glass, and the mirror constant is at a 60.038 MPaċmm0.5level. In addition, this suggests that the size of the crack flaws that may occur on the glass surfaces during the LCD process should be minimized to produce panels that can withstand a certain impact level through the fracture surface analysis of the glass crack origins. [ABSTRACT FROM PUBLISHER]

Published
2017
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45. Physiological enhancement of early growth of rice seedlings (Oryza sativaL.) by production of phytohormone of N2-fixing methylotrophic isolates

Author

Lee, Hyoung Seok, Madhaiyan, Munusamy, Kim, Chung Woo, Choi, Seung Ju, Chung, Keun Yook, and Sa, Tong Min

Abstract

Three plant-growth promoting, N2-fixing methylotrophic strains isolated from rice cultivars (Oryza sativaL.), viz, Methylobacteriumsp. CBMB20, Enterobactersp. CBMB30, Burkholderiasp. CBMB40, were selected, and their activities in promoting the early growth of rice were studied. Seeds treated with the methylotrophic strains improved seed germination, seedling vigor index (SVI), and biomass of rice seedlings. The methylotrophic population in the treated seedlings increased in the vegetative stages when compared to seeding stages. Treated seedlings showed a higher accumulation of plant hormones viz trans-zeatin riboside, isopentenyladenosine, and indole-3-acetic acid than untreated seedlings. Plant hormones were detected immunologically using the phytodetek kit. Conformational evidence suggested that cytokinins were produced by the epiphytic bacteria colonizing the plants rather than by the plants themselves. In addition, the inoculated early stage rice seedlings also exhibited a wide range of acetylene reduction activity. The results suggest the potential use of these bacteria to stimulate germination, SVI, and biomass production, which is mediated by production of plant hormone accumulation and nitrogen fixation.Three plant-growth promoting, N2-fixing methylotrophic strains isolated from rice cultivars (Oryza sativaL.), viz, Methylobacteriumsp. CBMB20, Enterobactersp. CBMB30, Burkholderiasp. CBMB40, were selected, and their activities in promoting the early growth of rice were studied. Seeds treated with the methylotrophic strains improved seed germination, seedling vigor index (SVI), and biomass of rice seedlings. The methylotrophic population in the treated seedlings increased in the vegetative stages when compared to seeding stages. Treated seedlings showed a higher accumulation of plant hormones viz trans-zeatin riboside, isopentenyladenosine, and indole-3-acetic acid than untreated seedlings. Plant hormones were detected immunologically using the phytodetek kit. Conformational evidence suggested that cytokinins were produced by the epiphytic bacteria colonizing the plants rather than by the plants themselves. In addition, the inoculated early stage rice seedlings also exhibited a wide range of acetylene reduction activity. The results suggest the potential use of these bacteria to stimulate germination, SVI, and biomass production, which is mediated by production of plant hormone accumulation and nitrogen fixation.

Published
2006
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46. Formate as Anti-Oxidation Additives for Pb-Free FASnI(3) Perovskite Solar Cells

Author

Jang, Hyungsu, Lim, Hyeong Yong, Yoon, Yung Jin, Seo, Jongdeuk, Park, Chan Beom, Son, Jung Geon, Kim, Jae Won, Shin, Yun Seop, An, Na Gyeong, Choi, Seung Ju, Kim, Su Hwan, Jeong, Jaeki, Jo, Yimhyun, Kwak, Sang Kyu, Kim, Dong Suk, and Kim, Jin Young

Subjects
lead, ch3nh3pbi3, fabrication, stability, formate additives, perovskite solar cells, solvent, efficient, hysteresis, coordinate bonds, tin halide perovskites, halide passivation, pb-free perovskites, suppression of oxidation, performance, defects, sn-based perovskites
Abstract

Pb-free Sn-based perovskite solar cells (PSCs) have significant potential for application in photovoltaic devices because oftheir suitable bandgap, low exciton binding energy, high carrier mobility, and long diffusion length. However, their performance is hampered by several issues. Sn-based perovskites are highly susceptible to oxidation, which induces a high concentration of defects and degrades the chemical stability of the perovskite crystals. Herein, the anion formate (HCOO-) can effectively suppress the oxidation of Sn in the pure formamidinium tin triiodide (FASnI(3)) perovskite without using A-site cationic additives. Moreover, the presence of formate results in a uniform pinhole-free perovskite film with a low trap density, reduced charge carrier recombination, and improved charge extraction. Density functional theory calculations show that formate-treated FASnI(3) has improved stability against oxidative Sn degradation. The formate-treated PSC achieves a power conversion efficiency of 12.11% at a high open-circuit voltage of 0.71 V. The device exhibits improved stability in ambient air in which it maintained over 80% of its initial power conversion efficiency after 180 min because oxidation is inhibited owing to the strong interaction between Sn and formate.

47. Pseudo-halide anion engineering for α-FAPbI3 perovskite solar cells

Author

Jeong, Jaeki, Kim, Minjin, Seo, Jongdeuk, Lu, Haizhou, Ahlawat, Paramvir, Mishra, Aditya, Yang, Yingguo, Hope, Michael A., Eickemeyer, Felix T., Kim, Maengsuk, Yoon, Yung Jin, Choi, In Woo, Darwich, Barbara Primera, Choi, Seung Ju, Jo, Yimhyun, Lee, Jun Hee, Walker, Bright, Zakeeruddin, Shaik M., Emsley, Lyndon, Rothlisberger, Ursula, Hagfeldt, Anders, Kim, Dong Suk, Grätzel, Michael, and Kim, Jin Young

Abstract

Metal halide perovskites of the general formula ABX3—where A is a monovalent cation such as caesium, methylammonium or formamidinium; B is divalent lead, tin or germanium; and X is a halide anion—have shown great potential as light harvesters for thin-film photovoltaics1,2,3,4,5. Among a large number of compositions investigated, the cubic α-phase of formamidinium lead triiodide (FAPbI3) has emerged as the most promising semiconductor for highly efficient and stable perovskite solar cells6,7,8,9, and maximizing the performance of this material in such devices is of vital importance for the perovskite research community. Here we introduce an anion engineering concept that uses the pseudo-halide anion formate (HCOO−) to suppress anion-vacancy defects that are present at grain boundaries and at the surface of the perovskite films and to augment the crystallinity of the films. The resulting solar cell devices attain a power conversion efficiency of 25.6 per cent (certified 25.2 per cent), have long-term operational stability (450 hours) and show intense electroluminescence with external quantum efficiencies of more than 10 per cent. Our findings provide a direct route to eliminate the most abundant and deleterious lattice defects present in metal halide perovskites, providing a facile access to solution-processable films with improved optoelectronic performance.

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