Perovskite Crystals

Due to the unique optical properties and high quantum efficiency, the lead halide perovskites have obtained great attentions in the recent years. Currently, the research focuses not only on their potential applications in solar cell, LED, and laser, but also on several unsolved fundamental issues, such as the origin of the luminescence of Cs₄PbBr₆. The mechanism of the luminescent Cs₄PbBr₆ perovskite is still under debate. Some people think that the pure Cs₄PbBr₆ crystals are non-emissive while the strong green PL (Photoluminescence) originates from the CsPbBr₃ nanocrystals encapsulated in the Cs₄PbBr₆ bulk crystals. The others claim that the strong emissive comes from the structural defects of the Cs₄PbBr₆ crystals. Despite the various reports to support each opinion, no final conclusion has been made up to now. In this work, we plan to controllably synthesize emissive and non-emissive Cs₄PbBr₆ crystals as well as CsPbBr₃ nanocrystals with a strong photoluminescence. By combining various techniques, such as Raman, XRD, (HR)TEM, PL, etc., we attempt to confirm the contribution of CsPbBr₃ dopants to the the photoluminescent Cs₄PbBr₆ crystals.