First-Principles Investigation of the Semiconducting Behavior in Hybrid CH3N H3P bBr3 Perovskite Using the Quantum ESPRESSO Simulation Suite

Abstract

This study explores the electronic and structural characteristics of cubic methylammonium lead bromide (CH3NH3PbBr3) through Density Functional Theory (DFT) calculations performed with Quantum ESPRESSO. Following rigorous convergence benchmarks (Ecutwfc = 35 Ry, Ecutrho = 300Ry, and a 3 × 3 × 3 k-point grid), the simulated X-ray diffraction patterns verified the phase purity and high crystallinity of the cubic lattice. Our results identify a direct band gap of 2.01 eV situated at the R high-symmetry point. Analysis of the Partial Density of States (PDOS) reveals that the Valence Band Maximum is primarily composed of Pb(p) and Br(p) states, while the Conduction Band Minimum is governed by Pb(p) anti-bonding orbitals. These findings underscore the material’s suitability for optoelectronic devices operating in the visible spectrum (λ ≈ 617 nm).