Surface Charge Trapping in Organolead Halide Perovskites Explored by Single-Particle Photoluminescence Imaging

Organometal halide perovskites have attracted considerable attention because of their striking electrical and optical properties that are desirable for application in solar cells and optoelectronic devices; however, the structure-related dynamics of photogenerated charges are almost always masked by ensemble averaging in conventional spectroscopic methods, making it difficult to clarify the underlying mechanism. Here we investigate the photoluminescence characteristics of CH₃NH₃PbBr₃ perovskite nanoparticles using single-particle spectroscopy combined with electron microscopy. The in situ analysis of light and Lewis-base-induced surface passivation revealed that the photoluminescence quenching and blinking phenomena of single CH₃NH₃PbBr₃ nanoparticles are most probably caused by charge trapping at surface states, where the number of effective trapping sites was estimated to be 1–4 per particle