Optical Properties Optoelectronic Materials Photovoltaic Applications

This study examines the structural, mechanical, optical, and electronic properties of sodium niobate (NaNbO₃) perovskite using first-principles calculations within Density Functional Theory (DFT). The Generalized Gradient Approximation (GGA) and pseudopotentials in Quantum ESPRESSO were used for all computations. The optimized lattice parameters confirmed that NaNbO₃ crystallizes in an orthorhombic structure with space group Pbnm. The calculated elastic constants and related moduli met Born’s criteria for mechanical stability. The Pugh and Poisson ratios show that the compound is near the brittle–ductile boundary. Band structure results indicate an indirect band gap of about 0.4 eV, with the valence band maximum at the Γ point and the conduction band minimum at the X point. The density of states revealed strong interaction between Nb-4d and O-2p orbitals, confirming covalent bonding within the Nb–O octahedra. These findings show that NaNbO₃ is a stable indirect semiconductor with potential use in optoelectronic and photovoltaic devices.