title: New insights into the band-gap narrowing of (N, P)-codoped TiO2 from hybrid density functional theory calculations.
abstract: The electronic properties of anatase-TiO(2) codoped by N and P at different concentrations have been investigated via generalized Kohn-Sham theory with the Heyd-Scuseria-Ernzerhof (HSE06) hybrid functional for exchange-correlation in the context of density functional theory. At high doping concentrations, we find that the high photocatalytic activity of (N, P)-codoped anatase TiO(2) vis-à-vis the N-monodoped case can be rationalized by a double-hole-mediated coupling mechanism [Yin et al., Phys. Rev. Lett. 2011, 106, 066801] via the formation of an effective N-P bond. On the other hand, Ti(3+) and Ti(4+) ions' spin double-exchange results in more substantial gap narrowing for larger separations between N and P atoms. At low doping concentrations, double-hole-coupling is dominant, regardless of the N-P distance.
authors.affiliation: The SEC Strategic Research Cluster, Centre for Synthesis and Chemical Biology, School of Chemical and Bioprocess Engineering, University College Dublin, Belfield, Ireland. run.long@ucd.ie
authors.forename: Run
authors.initials: R
authors.lastname: Long
authors.forename: Niall J
authors.initials: NJ
authors.lastname: English