Concerted Ion Migration and Diffusion‐Induced Degradation in Lead‐Free Ag₃BiI₆ Rudorffite Solar Cells under Ambient Conditions

Silver bismuth iodide (SBI) materials have recently gained attention as nontoxic alternatives to lead perovskites. Although most of the studies have been focusing on photovoltaic performance, the inherent ionic nature of SBI materials, their diffusive behavior, and influence on material/device stability is underexplored. Herein, AgBi 2 I 7 , Ag 2 BiI 5 , and Ag 3 BiI 6 thin films are developed in controlled ambient humidity conditions with a...