Perovskite‐Initiated Photopolymerization for Singly Dispersed Luminescent Nanocomposites

Abstract Metal halide perovskites have demonstrated rich photophysics and remarkable potential in photovoltaic and electroluminescent devices. However, the photoactivity of perovskite semiconductors in chemical processes remains relatively unexplored. Here, a general approach toward the synthesis of luminescent perovskite–polymer nanocomposites is reported, whereby perovskite nanocrystals are used as photoinitiators in the polymerization of vinyl monomers. The white‐light illumination of a perovskite–monomer mixture triggers a free‐radical chain‐growth polymerization process, giving rise to high molecular weight polymers of ≈200 kDa. The in situ growth of polymer chains from the perovskite crystal surface allows the formation of individually dispersed nanocrystal cores within an encapsulating polymer matrix, and leads to a significant threefold enhancement in photoluminescence quantum yield. This photoluminescence enhancement is attributed to the spatial separation of the perovskite nanocrystals and hence the deactivation of energy transfer to dark crystals. The resulting perovskite–polymer nanocomposites exhibit excellent stability against moisture and are shown to be useful as functional downconversion phosphor films for luminescent displays and lighting.