Fluid Chemistry of Metal Halide Perovskites

Solution‐processed metal halide perovskites (MHPs) have been rapidly developed worldwide, with much attention to fluid dynamic, fluid crystallization, and fluid interfaces, all falling within the realm of fluid chemistry. It is widely recognized that the theory of fluid chemistry has been proven to provide an effective means for the improvement of perovskite crystallization and the enhancement of perovskite solar cells (PSCs) performance. In this review, the fluid behavior and aging process of perovskite materials are first investigated, with emphasis on the related improvement methods and chemical mechanisms. Secondly, the internal crystallization chemistry, external interface chemistry and the large‐area PSCs based on the fluid chemistry are discussed. Finally, four specific directions for future studies of fluid chemistry of MHPs are proposed, aiming to harness the theoretical advantages of fluid chemistry and contribute to the industrialization of PSCs.