The interactions between halide perovskites and oxygen: From stages to strategies

Metal halide perovskites (MHPs) face stability challenges particularly due to their susceptibility to oxygen exposure, hindering their practical applications. Unraveling the complicated photophysical and photochemical behaviors of MHPs in the presence of oxygen is essential to overcome this obstacle. To address this critical issue, we aim to integrate the recent findings and elucidate the dynamics of perovskite-oxygen interactions. The interactions between MHPs and oxygen are clarified in four fundamental stages: adsorption on the surface, surface reactions, diffusion of reactive oxygen species (¹O₂, O₂⁻, O₂²⁻), and bulk reactions. We try to provide a comprehensive and nuanced understanding of these interactions, emphasizing the underlying mechanisms governing charge and energy transfers. Within this framework, we particularly discuss the pronounced vulnerability of tin (Sn)-based perovskites to oxygen and analyze the distinct factors that amplify this susceptibility. Following this, we summarize the impact of oxygen exposure on the photoelectric performance of MHPs and outline potential strategies to mitigate superoxide-mediated degradation pathways. Gaining a deeper understanding of the perovskite-oxygen interaction can offer valuable insights for material optimization and device design, ultimately enhancing stability against oxygen exposure.