Mechanistic insights into defect-governed ion migration and phase instability in mixed-halide perovskites

Key Points

• The study aims to understand how defects affect ion migration and phase stability in mixed-halide perovskites.
• Analyzed ion migration mechanisms in FAPb(I 1− x Br x ) 3 cells under various conditions.
• Investigated dark transport and halide interstitials as key factors in the migration process.
• Examined the effect of illumination on FA-cation migration and its correlation with defect density.
• Dark transport is primarily dominated by halide interstitials.
• Illumination activates the migration of FA-cations, which is linked to the presence of deep-level defects.
• A clear relationship between defect density and ion migration behavior was established.