Effect of Deposition Parameters on Luminescence Properties and Structure Evolution of CsPb₂Br₅ Phase in Cesium Lead Bromide Perovskite Films

Abstract

The cesium lead bromide perovskite thin films prepared by chemical vapor deposition (CVD) have excellent optoelectronic properties， but the thin films generally have two different phase structures， CsPbBr 3 and CsPb 2 Br 5 . In our work， CVD method is considered to prepare cesium lead bromide perovskite thin films， and the effects of reaction pressure and N 2 flow on CsPb 2 Br 5 in the thin films were studied by X-ray diffraction (XRD)， scanning electron microscopy(SEM)， energy dispersive spectroscopy(EDS) and fluorescence spectrometer. The results show that the change of the reaction pressure has no effect on the CsPb 2 Br 5 phase. However， with the decrease of the N 2 flow， part of the CsPb 2 Br 5 phase in the film gradually transforms into the CsPbBr 3 phase， and its luminescence also converts from a broadband emission dominated by ~630 nm to a narrowband emission dominated by ~530 nm. Experimental results reveal that N 2 flow is an effective means to control the phase structure and luminescence properties of CsPb 2 Br 5 .Key words： chemical vapor deposition (CVD)； cesium lead bromide perovskite film； CsPb 2 Br 5 phase