Stability of self-encapsulated CsPbX3@PbX(OH)(X=Cl,Br) perovskite quantum dots in polar solvents

Abstract

Inorganic halide perovskite quantum dots has excellent optical and photoelectric properties, so it has great potential in photovoltaic, photoelectric devices, display lighting, medical detection and other fields. However, its commercial application is hampered by its instability. In this paper, the perovskite quantum dots encapsulated by PbX (OH)(X = Cl,Br) can obtain hexahedral CsPbBr3@PbBr(OH), cube CsPbCl3@PbCl(OH) and spindle CsPbCl3@PbBr(OH) between hexahedron and cube. The core-shell encapsulation and interchange combination are realized. Before and after encapsulation, the color coordinates of CsPbX3 (X = Cl,Br) perovskite quantum dots basically did not change, no other crystal phases were found in the XRD lines, which indicatied that the PbX (OH) (X = Cl,Br) encapsulation layer did not change the crystal structure of perovskite quantum dots. PbX (OH) (X = Cl,Br) encapsulation layer plays the role of water-blocking layer and protective layer, which greatly improves the stability of CsPbX3 (X = Cl,Br) perovskite quantum dots in polar solvents. After encapsulation, the photoluminescence quantum yield (PLQY) and time-resolved photoluminescence decay performance of CsPbX3 (X = Cl,Br) perovskite quantum dots are greatly improved. The surface passivation and trap density of perovskite nanocrystals can be reduced by PbX (OH) (X = Cl,Br) wrapping, which extends the fluorescence life of CsPbX3 (X = Cl,Br) and improving the PL stability of perovskite structure. Room temperature (RT) crystallization method does not require inert gas protection, high temperature and high pressure conditions. It also has good repeatability, which provides a better alternative to hot injection. Meanwhile, the improvement of package stability provides a broader prospect for the application and promotion of lead halide perovskite.