Photoswitchable nanomaterials are key materials in the development of advanced imaging techniques, such as super‐resolution fluorescence microscopy. The combination of perovskite CsPbBr3 nanocrystals (NCs) with bright photoluminescence (PL) emission and diarylethenes (DAEs) with structural changes in response to ultraviolet (UV) and visible light is a promising candidate system. Herein, CsPbBr3 NCs are coupled with photochromic DAE molecules to control the PL emission from the NCs by light stimulation. The PL emission is successfully switched ON and OFF by alternating UV and visible light irradiation. Time‐resolved PL emission studies suggest that Förster resonance energy transfer from CsPbBr3 NCs to the closed‐ring form of DAE occurs after UV irradiation, and the PL emission is quenched. Upon visible‐light irradiation, DAE is converted to the open‐ring isomer, and the PL emission is restored. Femtosecond pump‐probe spectroscopy reveals that light stimulation induces not only energy transfer but also photoinduced electron transfer in the NC‐DAE pair on the picosecond timescale to form DAE radicals. Thus, it is suggested that the holes residing in the NCs react with the NCs, degrading the PL emission. Stable PL switching is realized using 2,2,6,6‐tetramethylpiperidine‐1‐oxyl (TEMPO) as a hole scavenger to avoid the reaction between the holes and NCs.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.