Significantly enhanced thermal and water stability of heterostructured CsPbBr3/Cs4PbBr6@PbS nanocrystals

Abstract

Despite excellent optoelectronic properties, the practical applications of halide perovskite nanocrystals (NCs) have been restricted by their intrinsic instability. In this study, heterostructured CsPbBr3/Cs4PbBr6@PbS NCs were successfully synthesized using a simple solvothermal method. CsPbBr3/Cs4PbBr6@PbS NCs exhibited strong fluorescence in visible and near infrared (NIR) region under excitation at 365 nm. Remarkably, the CsPbBr3/Cs4PbBr6@PbS NCs showed improved excellent thermal and humidity stabilities compared with CsPbBr3 NCs. The incorporation of PbS shell could passivate the surface of CsPbBr3/Cs4PbBr6 NCs, leading them to exhibit fluorescence at higher temperatures compared with CsPbBr3 NCs, their fluorescence was quenched completely until the temperature was close to 200 °C while the fluorescence of CsPbBr3 NCs disappeared at ∼100 °C. In addition, the incorporation of PbS shell also limit the etch effect of CsPbBr3/Cs4PbBr6 NCs by water molecules, rendering them to retain the fluorescence after several months of exposure to air. These findings demonstrate a simple yet effective approach to improving the stability of perovskite NCs, providing new possibilities for their utilization in various optoelectronic devices.