CsPbBrxCl3-x/Cs4PbBrxCl6-x core/shell nanocrystals: Blue-emitting perovskite scintillators for X-ray detection

Abstract

Metal halide perovskite nanocrystals have become a research hotspot in radiation detection due to their excellent optoelectronic properties. By embedding perovskite particles in an insulating matrix to form core/shell structure, their stability can be significantly enhanced. However, traditional solution synthesis methods have certain limitations in preparing core/shell structures with specific structures and compositions. In this research, a straightforward mechanochemical synthesis strategy was used to successfully prepare blue light emitting perovskite nanocrystals with CsPbBr_xCl_3-x as core and Cs₄PbBr_xCl_6-x as shell. This method not only improved the luminescence efficiency of the nanocrystals (with the photoluminescence quantum yield (PLQY) increasing from 44.07% to 63.63%), but also enhanced their X-ray detection capabilities and stability. The excellent stability of the sample is attributed to the protection of Cs₄PbBr_xCl_6-x, while the higher PLQY may be due to the passivation effect of the core/shell structure. During the synthesis process, effect of CsCl doping levels on the optical and structural properties of CsPbBr_xCl_3-x/Cs₄PbBr_xCl_6-x NCs was investigated to optimize the synthesis scheme of the core/shell structure. In summary, this study paves the way for the further development and application of X-ray detection technology by thoroughly analyzing the effect of the core/shell structure on the environmental stability and detection performance.