Electronic Structure and Visible-Light Absorption of Transition Metals (TM=Cr, Mn, Fe, Co) and Zn-Codoped SrTiO3: a First-Principles Study**Supported by the National Natural Science Foundation of China under Grant No 51474011, the Postdoctoral Science Foundation of China under Grant No 2014M550337, and the Key Technologies R&D Program of Anhui Province of China under Grant No 1604a0802122.

Abstract

First-principles calculations are performed on the influence of transition metal (TM=Cr, Mn, Fe, Co) as codopants on the electronic structure and visible-light absorption of Zn-doped SrTiO3. The calculated results show that (Zn,Mn)-codoped SrTiO3 requires the smallest formation energy in four codoping systems. The structures of the codoped systems display obvious lattice distortion, inducing a phase transition from cubic to rhombohedral after codoping. Some impurity Cr, Mn and Co 3d states appear below the bottom of conduction band and some Fe 3d states are located above the top of valence band, which leads to a significant narrowing of band gap after transition metal codoping. The enhancement of visible-light absorption are observed in transition metals (TM=Cr, Mn, Fe, Co) and Zn codoped SrTiO3 systems. The prediction calculations suggested that the (Zn,Mn)- and (Zn,Co)-codoped SrTiO3 could be the desirable visible-light photocatalysts.