Non-fullerene acceptor pre-aggregates enable high efficiency pseudo-bulk heterojunction organic solar cells

• 作者: Donghui Li Chuanhang Guo Xue Zhang Baocai Du Cong Yu Pang Wang Shili Cheng Liang Wang Jinlong Cai Hui Wang Dan Liu Huifeng Yao Yanming Sun Jianhui Hou Tao Wang
• 来源期刊: 中国科学：化学（英文版）
• 年，卷（期）: 2022,（2）
• 所属期刊栏目: ARTICLES
• 页码范围: 373-381
• 页数: 9页
• 语种: 英文

摘要

Pseudo-bulk heterojunction(BHJ)fabricated by sequential casting of donor and acceptor layers has been recently demonstrated as a superior structure to prepare organic solar cells(OSCs)with enhanced efficiency compared to the conventional BHJ OSCs cast from a common solution of donors and acceptors.However,molecular diffusion and aggregation within the pseudo-BHJ layer bring great challenges to fully realize the advantage of pseudo-BHJ structure.Herein,a solution-incubated pre-aggregation strategy is employed to tune the nanoscale aggregates of non-fullerene acceptor(NFA)BTP-eC11 and N3 to substantially enhance device power-conversion efficiency(PCE).NFA pre-aggregates are incubated in solutions via aging or adding anti-solvent,and then sequentially cast onto D18 fibrillar network,which then penetrate to form a pseudo-BHJ structure with appropriate domain sizes to ensure superior charge mobilities.While the conventional pseudo-BHJ OSCs obtain inferior PCEs below 17％compared with normal BHJ OSCs,NFA pre-aggregates help to achieve remarkable PCEs of 17.7％and 17.5％for D18/BTP-eC11 and D18/N3 pseudo-BHJ OSCs.This work demonstrates that the solution-incubated nanoscale pre-aggregation is an efficient approach to regulate molecular diffusion and aggregation to guarantee high performance pseudo-BHJ OSCs.