Elucidating the mechanisms underlying PCBM enhancement of CH3NH3PbI3 perovskite solar cells using GIXRD and XAFS

Autor: Jiahao Wang, Xihong Guo, Bing Liu, Ying Li, Jinquan Dong, Baoyun Sun, Jing Zhang, Dangui Zhao, Huanli Yao, Yu Chen, Rongli Cui, Huan Huang
Rok vydání: 2020
Předmět:
Zdroj: Journal of Materials Chemistry A. 8:3145-3153
ISSN: 2050-7496
2050-7488
DOI: 10.1039/c9ta10763k
Popis: In this study, the stability mechanism of the optimized methyl ammonium lead triiodide (CH3NH3PbI3, MAPbI3)/[6,6]-phenyl-C61-butyric acid methyl ester (PCBM) perovskite active layer upon exposure to moisture, light, and heating was investigated. For the first time, the existence of high-valence lead arising from PCBM is confirmed by X-ray absorption fine spectroscopy (XAFS) based on synchrotron radiation, which helps to form stronger Pb–I bonds and facilitate carrier transport. Moreover, the degree of disorder of perovskites and the [PbI6]4− octahedral distortion are significantly improved, as well as the crystallization both on the surface and in the bulk. The result of this study provides a fundamental understanding of the functions of additives with electron-withdrawing properties (e.g., PCBM) in perovskite materials and could specifically be extended to systematically design and fabricate high-efficiency and stable solar cells.
Databáze: OpenAIRE