Strain Effect on the Electronic, Optical, and Mechanical Properties of Inorganic Mg3NBr3 Perovskite: A DFT Study

This study investigates the potential of lead-free Mg₃NBr₃ inorganic halide perovskites for photovoltaic and optoelectronic applications through comprehensive first-principles density functional theory (FP-DFT) calculations. This analysis reveals that Mg₃NBr₃ behaves as an indirect bandgap semiconductor with tunable electronic transitions in the visible spectrum region through strain engineering. The calculated bandgap values are 1.170 eV using the Perdew–Burke–Ernzerhof (PBE) functional without spin–orbit coupling (SOC), decreasing to 1.151 eV at the Γ and R-points when SOC effects are incorporated. The structural stability and mechanical properties of Mg₃NBr₃ were evaluated through elastic constants, bulk modulus, and Pugh's and Poisson's ratio calculations, confirming both mechanical stability and ductile behavior with notable anisotropic characteristics. The detailed optical characterization encompassed the calculation of dielectric functions, refractive indices, reflectivity spectra, and absorption coefficients are investigated. Its thermal properties indicate that it can withstand high temperatures. These findings suggest that Mg₃NBr₃ holds great promise as a cost-effective, high-performance, and nontoxic material for use in electrical devices, particularly in applications like solar cells and photovoltaic technology.