Enhanced Efficiency and Stability of Triple-Cation Perovskite Solar Cells through Engineering of the Cell Interface with Phenylethylammonium Thiocyanate.

It is reported that the tricationic mixed halide perovskite Cs(FAMA)Pb(IBr) (CsFAMA) possesses a stable crystal structure and outstanding bandgap tunability, rendering it one of the most competitive candidates for commercial perovskite solar cells (PSCs). Nevertheless, the numerous defects at the interface of the tricationic perovskite give rise to a significant constraint on the light capture performance of the device. Simultaneously, water molecules form intermediate compounds with the perovskite at the interface via hydrogen bonds, accelerating the degradation of the perovskite.