Photoreversible luminescence switching of CsPbI3 nanocrystals sensitized by photochromic AgI nanocrystals

Abstract

Smart fluorescent materials have attracted much attention due to their promising applications in various fields. Here, we demonstrate a reversible fluorescence switching of CsPbI₃ nanocrystals (NCs) using photochromic AgI NCs as the photosensitizer. Upon light irradiation, AgI NCs are decomposed into metallic Ag and elemental I₂, leading to the formation of Ag–CsPbI₃ heterostructures. Because Ag has a lower Fermi level than that of CsPbI₃, excited electrons will transfer from CsPbI₃ to Ag, resulting in the quenching of photoluminescence emission. When the composite is stored in the dark, metallic Ag is oxidized into AgI, and the PL emission of CsPbI₃ NCs can be recovered. The application of the AgI/CsPbI₃ system has been demonstrated as a rewritable platform. This work may shed light on the exploration of CsPbX₃ NCs for applications in smart fluorescent materials.