Facile Synthesis of CsPbBr3/K4–xNb6O17 Nanocomposites with Sandwich-like and Scroll-like Heterostructures

Cesium lead halide (CsPbX3, where X is Cl, Br, or I) perovskite quantum dots (QDs) hold great potential for applications in various devices, on account of their superior electronic and optical properties. However, the poor stability has severely restricted their applications. Herein, by exfoliating K4Nb6O17 into niobate nanosheets (KNO NSs) and utilizing the flocculation of KNO NSs as building blocks, the CsPbBr3/K4–xNb6O17 (CsPbBr3/KNO) nanocomposites were obtained via evaporation of a dimethyl sulfoxide (DMSO) solution and crystallization of CsPbBr3 nanocrystals. The as-synthesized CsPbBr3/KNO nanocomposites possess sandwich-like and scroll-like heterostructures, which consist of restacked KNO NSs and CsPbBr3 in the internanosheet gallery. CsPbBr3/KNO nanocomposites exhibit better exciton emission of CsPbBr3 with a prolonged emission decay time with reference to the value of CsPbBr3 QDs. In addition, the strong interaction at the interfaces of CsPbBr3 and KNO NSs endows CsPbBr3/KNO nanocomposites with significantly improved resistance to alcohol over bare CsPbBr3 QDs. This work paves a new way for utilizing oxide nanosheets as building blocks to synthesize stable all-inorganic perovskite QDs.