Crystal phase and band edge modulation of MA- and Br-free CsFA-based perovskite for efficient inverted solar cells and minimodules

A Lewis base is selected to regulate crystal growth, reduce δ-phase formation and inhibit halide oxidation of perovskites, enabling champion efficiencies of 26.12% for a 0.09-cm 2 inverted device and 22.67% for a 12.96-cm 2 minimodule, respectively.