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

Abstract Recently, all‐inorganic halide perovskite (CsPbX₃, (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 TiO₂@CsPbBr₃ hybrid architectures, in which TiO₂ nanoparticles (NPs) with a hard lattice as nano “balls” mill off the angles and anchor to the CsPbBr₃ NCs with a soft lattice. On the contrary, to ball‐mill without TiO₂ or with conventional ceramics balls replacing TiO₂, CsPbBr₃ NCs still maintain cubic contour deriving from their cubic crystal structures. Moreover, the TiO₂@CsPbBr₃ architectures display distinct improvement of photoluminescence quantum yields and more excellent thermal stability in contrast with pristine CsPbBr₃ owing to the passivation of surface defect, small surface area, and energy transfer from CsPbBr₃ to TiO₂. Meanwhile, there is distinct luminous decay characteristic under the radiation of UV and visible light due to the “on” and “off” TiO₂ response. The method provides an alternative strategy to acquire other anchoring heterojunctions based on perovskite NCs for further regulating their luminescent characteristics.