Title : All-inorganic cesium lead mixed-halide perovskite CsPbI2Br thin films: AgBr doping effects on material properties
Abstract:
All-inorganic perovskite semiconductors have received a significant interest for their potential stability over heat and humidity. However, the typical CsPbI3 displayed the phase instability in spite of its desirable bandgap of ~1.73 eV. Herein, we study the mixed halide perovskite CsPbI2Br by varying Ag-doping concentration. For this purpose, we examined its bandgap tenability as a function of Ag-doping level by using density functional theory (DFT). Then, we study the effect of Ag on the structural and optical properties of CsPbI2Br. Resultantly, we find that Ag-doping may not only allow partial bandgap tenability from 1.91 eV to 2.05 eV and increase photoluminescence (PL) lifetime from 0.990 ns to 1.187 ns, but also contribute to the structural stability according to the x-ray diffraction (XRD) data. Furthermore, through analysing the intermolecular interactions based on Hansen solubility parameter, the solvent engineering technique is explained in relation to the solvent trapping phenomena in the CsPbI2Br layer. However, Ag-doping may result in pinhole-like defect morphology in films when introduced into the perovskite precursor solution via AgBr ionic compound.
