Emerging Chemistry in Enhancing the Chemical and Photochemical Stabilities of Fused‐Ring Electron Acceptors in Organic Solar Cells

• Published in: Advanced functional materials 2021-12, Vol.31 (50), p.n/a
• Main Authors: Liu, Hongtao, Li, Yibin, Xu, Shaoheng, Zhou, Yinhua, Li, Zhong'an
• Format: Article
• Language: English
• Subjects: Bridges; chemical stability; Commercialization; Degradation; Electrons; Energy conversion efficiency; fused ring electron acceptors; Materials science; Nucleophiles; Organic chemistry; organic solar cells; photochemical stability; Photooxidation; Photovoltaic cells; Solar cells
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202106735

The power conversion efficiency of organic solar cells (OSCs) has made exceptionally rapid progress in the past five years owing to the emergence of fused‐ring electron acceptors (FREAs). To achieve the commercialization, it is urgent to resolve the stability issues of OCSs from materials to devices. In particular, the state‐of‐the‐art FREAs, often synthesized by Knoevenagel condensation, generally contain two exocyclic vinyl groups (CC bond) as the conjugated bridges, which inevitably exhibit an obvious electron‐deficient characteristic due to the strong push‐pull electronic effect. As a result, these vinyl bridges are vulnerable to nucleophile attacking and/or photooxidation, leading to poor chemical and photochemical stabilities of FREAs that easily cause the degradation of device performance. In this perspective, an in‐depth understanding of the degradation mechanism of FREAs is provided, and then effective strategies reported recently are reviewed for improving the chemical and photochemical stabilities of FREAs from interfacial engineering to molecular engineering to additive engineering. Finally, a conclusion and outlook for the future design of highly efficient and stable FREAs are also presented. Research on the stability of organic solar cells based on fused‐ring electron acceptors (FREAs) is now becoming more urgent. This perspective focuses on discussing the possible degradation mechanisms of FREAs and effective strategies of enhancing their stability reported recently. Also, a conclusion and outlook for the future design of highly efficient and stable FREAs are presented.