Efficient and stable inverted perovskite solar cells enabled by inhibition of self-aggregation of fullerene electron-transporting compounds

• 作者: Chengbo Tian German Betancourt-Solis Ziang Nan Kaikai Liu Kebin Lin Jianxun Lu Liqiang Xie Luis Echegoyen Zhanhua Wei
• 来源期刊: 科学通报（英文版）
• 年，卷（期）: 2021,（4）
• 所属期刊栏目: ARTICLES
• 页码范围: 339-346
• 页数: 8页
• 语种: 英文

摘要

Fullerene-based electron-transporting layers (ETLs) significantly influence the defect passivation and device performance of inverted perovskite solar cells (PSCs).However,the π-cage structures of fullerenes lead to a strong tendency to self-aggregate,which affects the long-term stability of the corresponding PSCs.Experimental results revealed that[6,6]-phenyl-C61-butyric acid methyl ester (PCBM)-based ETLs exhibit a certain degree of self-aggregation that affects the stability of the device,particularly under continuous irradiation stress.To modulate the aggregation behavior,we replaced a methyl hydrogen of PCBM with a phenyl group to yield[6,6]-phenyl-C61-butyric acid benzyl ester (PCBB).As verified through X-ray crystallography,this minor structural modification results in more non-covalent intermolecular interactions,which effectively enhanced the electron-transporting ability of the PCBB-based ETL and led to an efficiency approaching 20％.Notably,the enhanced intermolecular forces of PCBB suppressed its self-aggregation,and the corresponding device showed significantly improved stability,retaining approximately 90％ of its initial efficiency after 600 h under one-sun irradiation with maximum power point tracking.These findings provide a viable approach for the design of new fullerene derivatives to tune their intermolecular interactions to suppress self-aggregation within the ETL for high-performance PSCs.