Structure, electronic and optical properties of CsPbX3 halide perovskite: A first-principles study

CsPbX3 (X = halide) perovskites have promising optoelectronic application in solar cells, light-emitting diodes, and photodetection. Here, we report the atomic structure, electronic and optical properties of CsPbX3 (X = I, Br, Cl, mixed-halide) using density functional theory calculations. The structure of CsPbX3 changes with the change of halide ratio. All the CsPbX3 compounds are direct bandgap semiconductors, and their valence band maximum is dominated by halide p orbitals, hybridizing with Pb 6s orbitals. With the gradually increasing of the lattice volume of the CsPbX3 primary cell, the corresponding band gap value decreases accordingly, and the absorption spectra are red-shifted. The carrier mobility performance is estimated by the effective mass calculation, showing feasible charge transport properties. By adjusting the halide ratio, CsPbX3 (X = I, Br, Cl, mixed-halide) possess the tunable band gap in the whole visible light range, which is of great significance for the development of new-type, high-efficient semiconductor materials and optoelectronic devices.