Bulk Restructure of Perovskite Films via Surface Passivation for High‐Performance Solar Cells

• Published in: Advanced energy materials Vol. 12; no. 33
• Main Authors: Xiong, Jian, Liu, Naihe, Hu, Xiaotian, Qi, Yifang, Liu, Weizhi, Dai, Junqian, Zhang, Yongsong, Dai, Zhongjun, Zhang, Xiaowen, Huang, Yu, Zhang, Zheling, Dai, Qilin, Zhang, Jian
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01-09-2022
• Subjects: Butyric acid; Control equipment; Crystal defects; Energy conversion efficiency; Grain size; Interface stability; interfaces; inverted PSCs; N‐benzyloxycarbonyl‐ d‐valine; Perovskites; Photovoltaic cells; post‐treatment; Solar cells; Valine
• ISSN: 1614-6832; 1614-6840
• DOI: 10.1002/aenm.202201787

Defects in perovskite films and the suboptimal interface contact largely limit the performance and stability of inverted perovskite solar cells (PSCs). A simple surface post‐treatment with N‐benzyloxycarbonyl‐d‐valine (NBDV) is developed to overcome these problems. The device performance following NBDV treatment is systemically investigated. It is showed that NBDV surface post‐treatment results in the bulk restructure of the entire perovskite film and improves the film‐forming property of [6,6]‐phenyl‐C61‐butyric acid methyl ester. The grain sizes, crystallinity, trap states, cathode interfaces, as well as the built‐in field are also improved, which result in PSC performance and stability enhancement. A relatively higher power conversion efficiency (PCE) of 21.80% is reached, which is comparable to the PCE record based on single‐crystal MAPbI3. Meanwhile, the PCE of the NBDV devices can retain ≈77% and 84% of the initial value after storage for 768 h (32 days) in air and 8376 h (349 days) in N2, respectively, while the control devices only maintain ≈53% and 38% of their initial PCE values under the same exposure conditions. This work provides means to promote bulk, surface, and interface regulation toward high performance and stable inverted PSCs.
N‐benzyloxycarbonyl‐d‐valine is demonstrated to be a simple surface post‐treatment material to improve the grain sizes, crystallinity, trap states, cathode interfaces, built‐in field as well as [6,6]‐phenyl‐C61‐butyric acid methyl ester film formation for perovskite solar cells. A relatively higher power conversion efficiency of 21.80% and good stability are obtained in the MAPbI3‐based inverted perovskite solar cells.