Thin Film of Perovskite (Mixed-Cation of Lead Bromide FA1−xMAxPbBr) Obtained by One-Step Method

Perovskite materials for solar cell applications were prepared by a one-step method. In the following work, the spin coating technique was used for organic–inorganic hybrid perovskite formamidinium lead tribromide (FAPbBr 3 ), methylammonium lead tribromide (MAPbBr 3 ) and formamidinium methylammonium lead tribromide (FA 1−x MA x PbBr 3 ).Thin films of mixed FA 1−x MA x PbBr 3 ( x = 0–1) perovskites deposited on indium tin oxide glass substrates were obtained by mixing FAPbBr 3 and MAPbBr 3 in different proportions. Structural x-ray diffraction (XRD), morphological (Scanning Electron Microscopy (SEM) and energy dispersive x-ray spectroscopy (EDX) and optical (uv–visible spectroscopy (UV–Vis) proprieties were investigated for all synthesized perovskites as a function of the MA/FA ratio. The (XRD) analysis shows the formation of a cubic-phase perovskite with space group Pm-3 m in the composition range 0 ≤ x ≤ 1. High absorbance levels were obtained in the infrared region 500-900 nm for mixed perovskites FAMAPbBr 3 . The estimated energy band-gap from the absorbance spectral measurements for FAMAPbBr 3 thin films was in the range of 2.2 eV for FAPbBr 3 and 2.3 eV for MAPbBr 3 , respectively. The photoluminescence emission of mixed FA/MA perovskite thin films was located in intermediate values between 580 nm and 555 nm.