SnO \(_{\varvec{2}}\) exhibits a wide bandgap ( \(\sim\) 3.6 eV) and a high exciton binding energy at room temperature, along with visible light transmittance exceeding 90%. Due to its unique optical, electrical, and stable physicochemical properties, it has been widely applied in various fields. In this study, we employed the hybrid functional HSE06 method within first-principles calculations to investigate the electronic structure and optical properties of intrinsic SnO \(_{\varvec{2}}\) as well as Pd-, Dy-, Gd-, Sm-, Ru-, Nd-, and Mo-doped SnO \(_{\varvec{2}}\) systems. Through these calculations, we obtained the electronic structure and optical properties (such as reflectivity and absorption spectra) of both doped and undoped systems. Based on the accurately computed band structures and density of states, we analyzed the related electronic and optical properties. The results demonstrate that the HSE06 method accurately predicts the bandgap of SnO \(_{\varvec{2}}\) , yielding values in close agreement with the experimental value of 3.6 eV. Furthermore, Dy- and Gd-doped SnO \(_{\varvec{2}}\) systems exhibit improved optical performance and enhanced electrical conductivity. With respect to optical properties, rare-earth doping (Nd, Sm, Gd, Dy) induces a redshift in the absorption edge, thereby extending the spectral response range. Compared to intrinsic SnO \(_{\varvec{2}}\) , the static dielectric constant decreases in the Nd-doped system but increases upon Sm, Gd, and Dy doping, which is beneficial for future research and application in optoelectronic devices.
