Highly stable and efficient α-phase FA-based perovskite solar cells prepared in ambient air by strategically enhancing the interaction between ions in crystal lattices

• Published in: Sustainable energy & fuels 2021-09, Vol.5 (17), p.4268-4276
• Main Authors: Zhao, Jingcheng, He, Guo, Yang, Dezhi, Guo, Dechao, Yang, Liqing, Chen, Jiangshan, Ma, Dongge
• Format: Article
• Language: English
• Subjects: Air temperature; Bonding strength; Chemical bonds; Crystal lattices; Crystal structure; Energy conversion efficiency; Hydrogen bonding; Hydrogen bonds; Lead; Maximum power tracking; Methylamine; Perovskites; Photovoltaic cells; Room temperature; Solar cells; Structural stability; Thiocyanates; Ultraviolet filters
• ISSN: 2398-4902; 2398-4902
• DOI: 10.1039/d1se00784j

FAPbI 3 perovskite is an ideal candidate for efficient and stable perovskite solar cells (PSCs). Unfortunately, attaining photoactive α-phase FAPbI 3 under humid conditions is rather difficult due to the structural and moisture instability of α-phase FAPbI 3 . To obtain high quality α-phase FAPbI 3 perovskite in ambient air, a strategy of incorporating methylamine thiocyanate (MASCN) as a stabilizer is introduced in this study. Due to its close effective ionic radius to I − , SCN − is successfully incorporated into the lattice. The strong bond between SCN − and Pb 2+ and the strong hydrogen bonds between the N atom in SCN − and FA + lead to a high quality and stable α-phase FA-based perovskite at ambient 50 ± 5% RH even at room temperature. With this high quality film, air-processed PSCs with a maximum power conversion efficiency (PCE) of 19.06% can be realized in a p-i-n device. Moreover, it is also demonstrated that the stronger chemical bonding interaction between SCN − and Pb 2+ as well as the stronger hydrogen bonds between SCN − and organic groups also improve the stability of PSCs. More than 90% of the initial efficiency is retained after 2000 hours of operation with maximum power point tracking under full sunlight illumination without an ultraviolet filter. An α-phase FA-based perovskite is successful stabilized in ambient air using MASCN by strong interaction between ions and strong hydrogen bonds.