First-principles calculation of compensated (2N, W) codoping impacts on band gap engineering in anatase TiO2

The electronic structures and optical properties of N-, W-, non-compensated (N, W) and compensated (2N, W) doped anatase TiO2 have been investigated using spin-polarized density functional theory. The calculated results demonstrate that compensated (2N, W) codoped TiO2 system not only gives rise to a much more effective band gap narrowing than non-compensated codoping and monodoping systems, but also forms the continuum states above the top of the valence band and eliminates the local energy states. We predict that compensated (2N, W) codoped TiO2 could serve as efficient visible-light photocatalyst.