Dopant‐Free Bithiophene‐Imide‐Based Polymeric Hole‐Transporting Materials for Efficient and Stable Perovskite Solar Cells

• DOI: 10.1002/adma.202110587
• Publication Date: 2022-10-03T10:15:26Z
• Authors: Yuanqing Bai; Zhisheng Zhou; Qifan Xue; Chunchen Liu; Ning Li; Haoran Tang; Jiabin Zhang; Xinxin Xia; Jie Zhang; Xinhui Lu; Christoph J. Brabec; Fei Huang
• Keywords: Passivation; Electron Mobility; Acceptor

The development of hole-transport materials (HTMs) with high mobility, long-term stability, and comprehensive passivation is significant for simultaneously improving the efficiency stability perovskite solar cells (PVSCs). Herein, two donor-acceptor (D-A) conjugated polymers PBTI PFBTI alternating benzodithiophene (BDT) bithiophene imide (BTI) units are successfully developed desirable hole mobilities due to good planarity extended conjugation molecular backbone. Both copolymers can be employed as HTMs suitable energy levels efficient defect passivation. Shortening alkyl chain BTI unit introducing fluorine atoms on BDT moiety effectively enhances mobility hydrophobicity HTMs, leading improved PVSCs. As a result, organic-inorganic hybrid PVSCs HTM deliver power conversion (PCE) 23.1% enhanced operational ambient which one best efficiencies reported dopant-free polymeric date. Moreover, applied in inorganic perovskite/organic tandem cells, achieving PCE 17.4% 22.2%, respectively. These results illustrate great potential an widely applicable cost-effective stable