Optical absorption of tri-doped (Mo, Y, N)-TiO2 with first-principle calculations

Abstract

In this theoretical study, a path was adapted to investigate the redshifting of the TiO2 absorption edge by molybdenum (Mo), yttrium (Y) and nitrogen (N) doping. The geometrical model, band gap and photo response were noted in the developed model of anatase TiO2. The tri-doped model showed very small modification in the structure as compared to a reference TiO2 model. The 3d states of Mo mix up with the 3d states of Ti, resulting in the reduction of band gap. The Y 2p states were introduced around the middle of the band gap of Y-doped TiO2. Good reduction was found in the gap of tri-doped TiO2 model and the created states were occupied. The doping of N via oxygen (O) substitution in tri-doped model resulted in the band gap reduction by introducing states in the band gap due to the mixing of N 2p and O 2p states.