Data on modeling FA and I losses in mixed-halide perovskites under light-induced degradation

The study develops a chemical rate-equation framework to model light-induced degradation in a triple-cation mixed-halide perovskite. The model tracks the time evolution of iodine and formamidinium losses and, in vacuum conditions, the emergence of metallic lead under continuous illumination. By analysing films with different bromide fractions (5–20%), the authors report improved photostability with higher bromide content within this range. The work also highlights that apparent stability can depend on the environment and on the diagnostic method, contrasting nitrogen and ultra-high-vacuum conditions and discussing limitations of XPS for detecting degradation in N₂.