First-Principles Study of the Structural and the Electronic Properties of the Lead-Halide-Based Organic Perovskites (CH3NH3)PbX3,( CH(NH2)2)PbX3

The electronic properties of MAPbX3(MA= CH3NH3+),FAPbX3(FA=( CH-(NH2)2+)(,X= I,Br,Cl) perovskite in the cubic phase are systematically studied using the first-principles calculations. Our calculations are performed using the Quantum-Espresso pakage in the framework of density functional theory (DFT). The projector augmented-wave (PAW) pseudopotentials are used within energy cutoff of 408 Ev for the plane-wave basis functions. The Monkhorst-Pack k-point mesh of 4 × 4 × 4 is employed. For the exchange-correlationfunctional, the generalized gradient approximation(GGA) of Perdew-Burke- Ernzerhof(PBE) is used to relax the structural parameters. spin-orbit coupling (SOC) is included in all the calculations. All calculations reported in agreement with experimental data.