Water-induced ultrastrong green emission in Cs4PbBr6 quantum dot glass

Abstract

The special luminescence properties of cesium lead halide perovskite make it an ideal material for efficient and low-cost light-emitting devices. However, the green emission observed in Cs₄PbBr₆ nanocrystals is still controversial, particularly whether it originates from the inherent point defects or only the CsPbBr₃ impurities. In this work, Cs₄PbBr₆ quantum dot glass was synthesized and the mechanism of the green emission in Cs₄PbBr₆ was systematically studied. The results show that the green emission of Cs₄PbBr₆ comes from the Br vacancies, and the water-induced hydration layer PbBr(OH) resulted in an enhancement of the green emission. The PLQYs of the quantum dot glass were increased 28 times with the assistance of water. This work provides evidence for the defect-induced green emission of Cs₄PbBr₆, which has significant value to related work and helps to extend the application range of zero-dimensional perovskite materials in optoelectronic devices.