Uniform incorporation of two-dimensional BiOBr into perovskite crystals and films to enhance photoluminescence

The all-inorganic perovskite nanocrystals are promising luminescent materials for optoelectronic devices. However, it is still a challenge to prepare perovskite nanocrystals with high luminescence. Herein, a synthesis method was developed for the uniform incorporation of ultra-thin BiOBr nanosheets into perovskite crystals at both body-embedding and surface-passivating positions. The micron-scale green-emitting phosphors composed of Cs 4 PbBr 6 nanocrystals and BiOBr nanosheets are prepared. The crystal structure of Cs 4 PbBr 6 nanocrystals can remain almost unchanged although prepared from different PbBr 2 concentrations. The luminescence mechanism of Cs 4 PbBr 6 is discussed. The Cs 4 PbBr 6 @BiOBr submicron phosphors can be dispersed in DMSO solvent without disintegration and dissolution, which are used as seeds of the CsPbBr 3 film growth. The CsPbBr 3 films with Cs 4 PbBr 6 @BiOBr doped exhibit pure optical characteristics of CsPbBr 3 , indicating that Cs 4 PbBr 6 is converted to CsPbBr 3 during the film preparation process. Furthermore, these Cs 4 PbBr 6 @BiOBr phosphors are mixed with CaAlSiN 3 : Eu red-emitting commercial phosphors to make white LEDs (WLEDs). Overall, this study provides a revealing insight into a kind of composite material constructed with halide perovskite and bismuth halide oxide.