2022 年 53 巻 1 号 p. 18-24
Organic–inorganic perovskites, such as methylammonium lead halide perovskites, have been receiving worldwide attention as a promising material for highly efficient solar cells and light-emitting devices. However, the halide ions inside the crystals are known to migrate even at room temperature, and this high flexibility causes issues such as reductions in both synthesis reproducibility and device durability. This article focuses on a recent set of studies that explore correlated structural transformation, functions, and photochemical reactions in the halide perovskites using single-molecule (particle) fluorescence spectroscopy and imaging. The single-particle reaction analysis will help to obtain microscopic information that are often hidden in ensemble-averaged measurements for deeper understanding of mechanisms and will open new avenues for extending the applications of halide perovskite materials.