Structural, electronic, and optical properties of undoped and Se-doped Sb2S3: A density functional theory study

This study employs a density functional theory (DFT) framework to investigate the structural, electronic, and optical enhancements induced by selenium (Se) doping in antimony sulfide (Sb₂S₃). Se incorporation reduces the bandgap from 1.70 eV (undoped) to 1.55 eV, attributed to orbital interactions among Se-4p, S-3p, and Sb-5p, which modify the electronic structure near the conduction and valence band edges. The optical properties analysis reveals significant changes with Se doping, including an increased extinction coefficient and enhanced absorption across the ultraviolet–visible spectrum, which improves Sb₂S₃’s light-harvesting efficiency. Furthermore, Se doping reduces dielectric anisotropy, decreases the refractive index, and reflectivity. These findings position Se-doped Sb₂S₃ as a promising candidate for optoelectronic applications, offering valuable insights into non-metal doping strategies for improved solar energy conversion.