Effects of oxygen defects on electronic band structures and dopant migration in Sn-doped TiO2 by density functional studies

In this work, we investigated the influence of oxygen vacancy on the electronic band structures and dopant migration properties of Sn-doped TiO2 (both rutile and anatase phases) using density functional calculations. Our results demonstrated that the oxygen vacancy could significantly reduce electronic band gaps of Sn-doped TiO2, and result in direct-indirect transition of band structures. The migration of interstitial Sn atom in rutile phase is found to be much easier than that in anatase phase, and the presence of oxygen vacancy can significantly reduce the migration barrier.