Enhancing the stability of CsPbBr3 nanocrystals by sequential surface adsorption of S2− and metal ions

Abstract

A sequential surface adsorption method for improving the photostability of perovskite nanocrystals (NCs) at room temperature was proposed. Firstly, S²⁻ was decorated on the surface of CsPbBr₃ NCs by adding didodecyl dimethylammonium sulfide (S²⁻-DDA⁺), and then In³⁺ ions, which diffused from the salt powder of In(Ac)₃, were slowly adsorbed by the pre-loaded S²⁻. Through this process, the photoluminescence quantum yield of the CsPbBr₃ NCs increases from 57% to 80%, and their photostability, thermal stability, and colloidal stability were all drastically improved. The resultant CsPbBr₃·S–In NCs remained stable for 188 h under strong LED light illumination (450 nm and 175 mW cm⁻²), while pristine CsPbBr₃ NCs totally quenched in 2 h, which shows the great potential of CsPbBr₃·S–In NCs in lighting and display applications. We also demonstrated that this method could be extended to many other metal salts to form stable perovskite·S–X (X = Ni, Mn and Zn) nanocrystals.