Electronic structure and enhanced visible-light absorption of N,B-codoped TiO2

We present GGA+U calculations to investigate the electronic structure and visible-light absorption of N,B-codoped anatase TiO2. The NsBi (substitutional N, interstitial B) codoped TiO2 produces significant Ti 3d and N 2p mid-gap states when the distance of N and B atoms is far, whereas the NiBi (interstitial N and B) and NsBs (substitutional N and B) codoped TiO2 prefer to form localized p states at 0.31.2 eV above the valence band maximum. Further, the optical band edges of the three codoped systems shift slightly to the visible region, but only the far-distance NsBi codoped TiO2 clearly shows an optical transition. These results indicate that NsBi codoped TiO2 has a dominant contribution to the optical absorption of N,B-codoped TiO2. (C) 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)