Nano Ball‐Milling Using Titania Nanoparticles to Anchor Cesium Lead Bromine Nanocrystals and Energy Transfer Characteristics in TiO₂@CsPbBr₃ Architecture

Abstract

Abstract Recently, all‐inorganic halide perovskite (CsPb X 3 , ( X = Cl, Br, and I)) nanocrystals (NCs) based hybrid architectures have attracted extensive attention owing to their distinct luminescence characteristics. However, due to stress and lattice mismatch, it is still a challenge to construct heterojunctions between perovskite NCs and the nanostructures with different lattice parameters and non‐cubic contour. In this work, a room temperature mechanochemical method is presented to construct TiO 2 @CsPbBr 3 hybrid architectures, in which TiO 2 nanoparticles (NPs) with a hard lattice as nano “balls” mill off the angles and anchor to the CsPbBr 3 NCs with a soft lattice. On the contrary, to ball‐mill without TiO 2 or with conventional ceramics balls replacing TiO 2 , CsPbBr 3 NCs still maintain cubic contour deriving from their cubic crystal structures. Moreover, the TiO 2 @CsPbBr 3 architectures display distinct improvement of photoluminescence quantum yields and more excellent thermal stability in contrast with pristine CsPbBr 3 owing to the passivation of surface defect, small surface area, and energy transfer from CsPbBr 3 to TiO 2 . Meanwhile, there is distinct luminous decay characteristic under the radiation of UV and visible light due to the “on” and “off” TiO 2 response. The method provides an alternative strategy to acquire other anchoring heterojunctions based on perovskite NCs for further regulating their luminescent characteristics.