The role of interfacial donor–acceptor percolation in efficient and stable all-polymer solar cells

• DOI: 10.1038/s41467-024-45455-0
• Publication Date: 2024-02-08T19:03:07Z
• Authors: Zhen Wang; Yu Guo; Xianzhao Liu; Wenchao Shu; Guangchao Han; Kan Ding; Subhrangsu Mukherjee; Nan Zhang; Hin-Lap Yip; Yuanping Yi; Harald Ade; Philip C. Y. Chow
• Keywords: Acceptor; Miscibility; Percolation (cognitive psychology); Degree of polymerization

Abstract Polymerization of Y6-type acceptor molecules leads to bulk-heterojunction organic solar cells with both high power-conversion efficiency and device stability, but the underlying mechanism remains unclear. Here we show that exciton recombination dynamics polymerized acceptors (Y6-PAs) strongly depends on degree aggregation. While fast rate in aggregated Y6-PA competes electron-hole separation at donor–acceptor (D–A) interface, much-suppressed dispersed is sufficient allow efficient free charge generation. Indeed, our experimental results theoretical simulations reveal Y6-PAs have larger miscibility donor polymer than small molecular acceptors, leading D–A percolation effectively prevents formation aggregates interface. Besides enabling generation efficiency, interfacial also improves thermodynamic stability blend morphology, as evident by reduced “burn-in” loss upon illumination.