Activated Corrosion and Recovery in Lead Mixed-Halide Perovskites Revealed by Dynamic Near-Ambient Pressure X-ray Photoelectron Spectroscopy

/light catalyst is removed, postulated to be due to mobile halide species present within the film below XPS sampling depth. Small deviations in near-surface composition (<2%) of the perovskite are used to connect reaction rates to quantified, near-band edge donor and acceptor defect concentrations, demonstrating two energetically distinct sites are responsible for the redox process. Collectively, environmental flux and rate quantification are deemed critical for the future elucidation of chemical degradation processes in perovskites, where rate-dependent reaction pathways are expected to be very system dependent (environment and material).