https://scholar.dgist.ac.kr/handle/20.500.11750/59211 2026-04-06T04:48:05Z https://scholar.dgist.ac.kr/handle/20.500.11750/60043 Title: Constructing High-Performance Solar Cells by Incorporating an A1-A2-Type Polymer Donor as a Guest Material Author(s): Li, Min; Chen, Guo; Lan, Ai; Chung, Sein; Que, Mingming; Cho, Yongjoon; Huang, Bin Abstract: Owing to the intramolecular push-pull electron effect between the electron donor (D) unit and electron acceptor (A) unit, the D-A type based polymer donors display outstanding device performance. However, the imperfect energy levels lead to the D-A-type-based polymer device exhibiting high voltage loss. In this study, an A1-A2-type copolymer M1 was developed with 1,3-bis(2-ethylhexyl)-5,7-di(thiophen-2-yl)benzo[1,2-c:4,5-c']dithiophene-4,8-dione (BDD) as the A1 unit and dithieno[3 ',2 ':3,4;2 '',3 '':5,6]benzo[1,2-c][1,2,5]thiadiazole (DTBT) as the A2 unit. Compared with D-A-type-based polymer donor PM6, the A1-A2 type based M1 possesses lower energy levels, broader absorption, and stronger crystallinity. After introducing M1 to the PM6:L8-BO-based system as the guest material, the ternary blend films exhibited exceptional face-on molecular orientation and favorable active-layer morphology, which promotes exciton dissociation and suppresses charge recombination. Consequently, the PM6:M1(5%):L8-BO-based ternary device exhibited an impressive power conversion efficiency (PCE) of 19.70% with simultaneously enhanced photostability, which is superior to the PM6:L8-BO-based binary system. Our work offers an efficient approach to developing high-performance ternary devices by introducing a novel A1-A2 type polymer donors as the guest material. 2025-11-30T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/60042 Title: Tailoring Molecular Orientation with a Polymer Additive Enables Bilayer Organic Solar Cells with 20.2% Efficiency Author(s): Zhao, Zhenmin; Chung, Sein; Zhong, Jiancheng; Yu, Xuemeng; Bai, Liang; Tan, Lixing; Pang, Wei; Zhang, Jingrong; Wei, Wuning; Chen, Guanlin; Li, Xin; Azeez, Abdul; Huang, Yexiao; Cho, Yongjoon; Wang, Mingcong; Cho, Kilwon; Kan, Zhipeng; Karuthedath, Safakath Abstract: Tuning the molecular packing from the edge-on to the preferred face-on orientation is beneficial for improving vertical charge transport and the photovoltaic performance in organic solar cells. However, achieving precise control over this structural transition remains a significant challenge due to the complex processing conditions. Herein, a trace amount of the polymer donor PTO2 as an additive, effectively inducing a preferential face-on molecular orientation in the acceptor phase is incorporated. This strategy enhanced exciton dissociation efficiency, improved charge carrier extraction, reduced trap density, and subsequently achieved a fill factor (FF) nearing 80%, results in a power conversion efficiency (PCE) of 20.2%, the highest reported for bilayer OSCs. Remarkably, the PTO2-driven molecular orientation strategy maintains consistent efficacy across diverse donor-acceptor systems, highlighting its broad applicability. This approach offers a comprehensive insight for the effective modulation of NFA molecular orientation, paving a practical approach for high-performance bilayer OSCs.