First-Principles Prediction of Optoelectronic Properties and Photocatalytic Potential of SrMnO₃ Perovskite Oxide

Abstract

Perovskite oxides are among the most versatile functional materials, widely studied for applications in energy conversion and electronic devices. In this study, density functional theory (DFT) with Hubbard U correction was applied to examine the structural, electronic, and optical properties of SrMnO₃. The lattice structure was optimized, and the resulting electronic band structure indicated a direct bandgap of approximately 2.1 eV, suitable for visible light absorption. Partial density of states analysis revealed that Mn 3d and O 2p orbitals dominate near the Fermi level, enabling strong electronic transitions under visible irradiation. Optical property simulations, including absorption spectra, refractive index, and dielectric constants, confirmed high absorption efficiency between 400–700 nm, making the material suitable for photocatalysis and solar cell applications. The band edge positions relative to water oxidation and reduction potentials suggest SrMnO₃ is thermodynamically capable of driving photocatalytic water splitting. Charge density mapping further demonstrated strong orbital hybridization, contributing to enhanced stability. These predictive insights provide a computational foundation for experimental exploration and potential modification of SrMnO₃ perovskite for optoelectronic and energy conversion applications.