The electronic structure and optical properties of rutile TiO₂ co-doped with nickel and cerium

This paper used the first-principle calculations based on the density functional theory (DFT) to determine the electronic structure and optical absorption of rutile TiO₂ co-doped with nickel (Ni) as a transition metal and cerium (Ce) as a rare earth metal. The calculated results demonstrated that the nickel and cerium TiO₂ co-doping induced impurity energy levels above the valence band maximum (VBM) which reduced the required electron transition energy and limit the recombination rate of charge carriers, as well as prolonging their life span. Likewise, the optical spectra of TiO₂ co-doped with nickel and cerium revealed a larger photo-response for visible light than that of nickel or cerium, single doped TiO₂.