Inorganic surface passivation strategies of metal halide perovskites

Abstract Metal halide perovskites have demonstrated considerable promise across various optoelectronic applications. Surface passivation serves as a pivotal strategy to obtain high‐quality perovskite materials, either in a manner of bulk thin film or nanocrystal, with superior optoelectronic properties and stability. The current research focus in this regard primarily revolves around the use of organic molecules to passivate the surface of perovskites. However, organic passivation molecules always suffer from chemical instability and weak secondary bonding modes, resulting in an unstable surface passivation motif. Inorganic materials, possessing more stable chemical structures and stronger chemical bonding than their organic counterparts, offer the opportunities to construct more robust passivation for the perovskite surfaces. Herein, in this review, we summarized and assessed recent advancements in inorganic surface passivation strategies for perovskite materials and devices, ranging from nanocrystals to bulk films. By discussing the mechanisms behind various inorganic passivation strategies, we aim to offer mechanistic insights and guidelines for future developments of more targeted surface passivation approaches tailored for perovskite materials and devices.