First-principles calculations on electronic structures of Fe-vacancy-codoped TiO2 anatase (101) surface

• DOI: 10.1016/j.physb.2011.07.007
• Publication Date: 2011-07-22T17:32:36Z
• Authors: Qi Li Chen; Bo Li; Guang Zheng; Kai Hua He; An Shou Zheng
• Keywords: Pseudopotential

Abstract The electronic structures of Fe-doped TiO2 anatase (1 0 1) surfaces have been investigated by all spin-polarized density functional theory (DFT) plane-wave pseudopotential method. The general gradient approximation (GGA)+U (Hubbard coefficient) method has been adopted to describe the exchange-correlation effects. Through the density functional calculations for the formation energies of various configurations, the complex of a substitutional Fe plus an O vacancy was found to form easily in the most range of O chemical potential. The calculated density of the states of the system of Fe-doped surface with a surface oxygen vacancy shows a band gap narrowing from 2.8 to 1.9 eV comparing with the pure surface due to the synergistic effects of surface Fe impurities with O vacancies. The system processes high visible light sensitivity and photocatalytic ability by decreasing extrinsic absorption energy. By comparing the partial DOS of some O and Ti atoms lying in the outermost and bottom layers of Fe-doped surfaces, it was found that the influence of Fe impurities on the electronic structure of the system is localized.