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.