Constructing a Strongly Absorbing Low‐Bandgap Polymer Acceptor for High‐Performance All‐Polymer Solar Cells

• Published in: Angewandte Chemie International Edition 2017-10, Vol.56 (43), p.13503-13507
• Main Authors: Zhang, Zhi‐Guo, Yang, Yankang, Yao, Jia, Xue, Lingwei, Chen, Shanshan, Li, Xiaojun, Morrison, William, Yang, Changduk, Li, Yongfang
• Format: Article
• Language: English
• Subjects: Absorption; Absorptivity; Chemical synthesis; Embedding; energy conversion; Energy conversion efficiency; Fullerenes; organic electronics; photoinduced force microscopy; Photovoltaic cells; Polymerization; Polymers; Solar cells
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201707678

All‐polymer solar cells (all‐PSCs) offer unique morphology stability for the application as flexible devices, but the lack of high‐performance polymer acceptors limits their power conversion efficiency (PCE) to a value lower than those of the PSCs based on fullerene derivative or organic small molecule acceptors. We herein demonstrate a strategy to synthesize a high‐performance polymer acceptor PZ1 by embedding an acceptor–donor–acceptor building block into the polymer main chain. PZ1 possesses broad absorption with a low band gap of 1.55 eV and high absorption coefficient (1.3×105 cm−1). The all‐PSCs with the wide‐band‐gap polymer PBDB‐T as donor and PZ1 as acceptor showed a record‐high PCE of 9.19 % for the all‐PSCs. The success of our polymerization strategy can provide a new way to develop efficient polymer acceptors for all‐PSCs. Energy conversion: Embedding an acceptor–donor–acceptor‐structured organic semiconductor building block into a polymer main chain creates an excellent low‐band‐gap polymer acceptor with red‐shifted absorption and a high absorption coefficient. The polymer acceptor provides a record‐high power conversion efficiency of 9.19 % for all‐polymer solar cells.