Eur. Phys. J. B (2020) 93: 201
https://doi.org/10.1140/epjb/e2020-10368-x

Regular Article

Structural, electronic and optical properties of S-doped, Sc-doped and Sc–S co-doped anatase TiO₂: a DFT + U calculation^★

¹ Department of Physics, East China Jiaotong University, Nanchang 330013, P.R. China
² Spallation Neutron Source Science Center, Institute of High Energy Physics, Chinese Academy of Sciences, Dongguan 523803, P.R. China

^a e-mail: xiongkw@ecjtu.edu.cn

Received: 21 July 2020
Received in final form: 10 September 2020
Accepted: 14 September 2020
Published online: 4 November 2020

Abstract

Defect formation energies, electronic structures and optical properties of non-metal S, lanthanide metal Sc-doped and Sc–S co-doped anatase TiO₂ were systematically investigated via a GGA + U method based on density functional theory (DFT). The on-site Coulomb corrections were applied to both 3d orbitals of Ti atom (U_{Ti_3d}) and 2p orbitals of O atom (U_{O_2p}). The results show all doped TiO₂ systems exhibit a certain degree of red-shift due to the presence of impurity levels in the bandgap; in particular, the S-doped and Sc–S co-doped TiO₂ exhibit better light absorption properties in the visible light range than either pure or Sc-doped TiO₂. In addition, the positive synergistic effect between the Sc and S atoms not only expands the absorption edge, but also increases the light absorption coefficient in the visible region. As a result, the Sc–S co-doped anatase TiO₂ shows the best optical absorption spectrum in all doping systems.