Electronic structure and optical properties of C-Pt codoped anatase TiO2 by first principles

The optical properties of TiO2 are changed while doped with impurity atoms. Among the crystal morphology of doped TiO2, systematical study of C-Pt codoped TiO2 influence on optical properties has never been reported. The paper made a systematical calculation of the band gap, density of states, optical properties for pure TiO2, doped C/Pt and codoped C-Pt anatase TiO2 according to first principle. It was shown that the structure of codoped C-Pt system is rather stable; the band gap of TiO2 was reduced; the impurity level of forbidden band is composed of C 2p and Pt-5d; red shift of optical absorption is produced and broaden to visible light region; the absorption power is improved dramatically. Among those three codoped systems, the optical properties red shift of Ti6Pt2O15C is the most obvious and optical absorption is the strongest.