First-principles study on the electronic and optical properties of F- and Nb-doped anatase TiO2

We present a comparative study on the electronic and optical properties of Nb- and F- doped anatase TiO2 by first-principles calculations based on the density functional theory (DFT). Although both TiO2:Nb and TiO2:F have a similar band structure, the effective mass of TiO2:F is larger than that of TiO2:Nb, and the carriers density in the former is lower than that in the latter, indicating that TiO2:Nb has better electronic conductivity than TiO2:F. The interaction between photons and electrons in TiO2:F is much stronger than that in TiO2:Nb, resulting in increased photon absorption and reduced transmittance, especially in the visible and near-infrared regions. The results demonstrate that TiO2:F is not suitable for transparent conductive oxide applications.

► Nb and F doped anatase TiO2 have a similar band structure.
► TiO2:F shows a larger effective mass in the bottom of conduction band with regard to TiO2:Nb.
► The ionization efficiency of Nb in TiO2:Nb is much larger than F in TiO2:F.
► The interaction between photons and electrons is stronger in TiO2:F, indicating more light will be absorbed in TiO2:F than that in TiO2:Nb.
► TiO2:F is not suitable for utilizing as a transparent conductive oxide.