Electronic and optical properties analysis on Bi/N-codoped anatase TiO2

The lattice parameters, band structures, electronic density of states and absorption spectra of Bi/N-codoped anatase TiO2 were calculated using the first-principles method based on the density functional theory. It was found that doping of the lattice distorted the tetragonal crystal, which would increase the dipole moment and this is beneficial to the separation of electrons and holes. Compared with pure TiO2, the band gap of Bi/N-codoped anatase TiO2 increases a little of 0.069 eV, Bi/N codoping induces some impurity energy levels above the valence band maximum (VBM) and below the conduction band minimum (CBM), which reduces the energy required for electrons transition. The absorption spectra indicate Bi/N codoping induces redshift and absorption enhancement of visible light. It is expected that Bi/N-codoped anatase TiO2 could be a good choice for visible light-driven photocatalyst.