High‐Performance All‐Polymer Solar Cells: Synthesis of Polymer Acceptor by a Random Ternary Copolymerization Strategy

• Published in: Angewandte Chemie International Edition Vol. 59; no. 35; pp. 15181 - 15185
• Main Authors: Du, Jiaqi, Hu, Ke, Meng, Lei, Angunawela, Indunil, Zhang, Jinyuan, Qin, Shucheng, Liebman‐Pelaez, Alex, Zhu, Chenhui, Zhang, Zhanjun, Ade, Harald, Li, Yongfang
• Format: Journal Article
• Language: English
• Published: WEINHEIM Wiley 24.08.2020; Wiley Subscription Services, Inc
• Edition: International ed. in English
• Subjects: Chemical synthesis; Chemistry; Chemistry, Multidisciplinary; Copolymerization; Copolymers; Energy conversion efficiency; Energy levels; mechanical properties; Morphology; Photovoltaic cells; Physical Sciences; Polymers; Science & Technology; Solar cells; synthetic methods; copolymerization; MOLECULAR-WEIGHT; MOBILITY; DONOR; CHARGE-TRANSPORT; polymers; solar cells; ELECTRON-ACCEPTOR; mechanical properties; synthetic methods; AGGREGATION
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202005357

Demonstrated in this work is a simple random ternary copolymerization strategy to synthesize a series of polymer acceptors, PTPBT‐ETx, by polymerizing a small‐molecule acceptor unit modified from Y6 with a thiophene connecting unit and a controlled amount of an 3‐ethylesterthiophene (ET) unit. Compared to PTPBT of only Y6‐like units and thiophene units, PTPBT‐ETx (where x represents the molar ratio of the ET unit) with an incorporated ET unit in the ternary copolymers show up‐shifted LUMO energy levels, increased electron mobilities, and improved blend morphologies in the blend film with the polymer donor PBDB‐T. And the all‐polymer solar cell (all‐PSC) based on PBDB‐T:PTPBT‐ET0.3 achieved a high power conversion efficiency over 12.5 %. In addition, the PTPBT‐ET0.3‐based all‐PSC also exhibits long‐term photostability over 300 hours. All‐polymer solar cells (all‐PSCs) are composed of polymer donors and acceptors, which hold potentially superior morphological stability and mechanical flexibility. In this work, a new random ternary copolymerization strategy was adopted to synthesize new polymer acceptors with high performance. The all‐PSCs based on the new polymer acceptor shows high power conversion efficiency of over 12.5 % and high photostability capable of withstanding long‐term illumination stress.