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

作者：Zhao, Jingcheng; He, Guo; Yang, Dezhi^*; Guo, Dechao; Yang, Liqing; Chen, Jiangshan; Ma, Dongge^*

来源：Sustainable Energy & Fuels, 2021, 5(17): 4268-4276.

DOI：10.1039/d1se00784j

• LOW-TEMPERATURE
• LEAD
• STABILIZATION
• STABILITY
• CATIONS

FAPbI(3) perovskite is an ideal candidate for efficient and stable perovskite solar cells (PSCs). Unfortunately, attaining photoactive alpha-phase FAPbI(3) under humid conditions is rather difficult due to the structural and moisture instability of alpha-phase FAPbI(3). To obtain high quality alpha-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 Pb2+ and the strong hydrogen bonds between the N atom in SCN- and FA(+) lead to a high quality and stable alpha-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 Pb2+ 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.