Improving the photo-response of TiO2 by tri-doping: a DFT based atomistic study

Abstract

Stabilizing the doped TiO2 structure along with broad absorption in the visible regime is helpful in improving its efficiency under solar irradiations. With ab-initio calculations, the mono-doped, co-doped and tri-doped systems of indium (In), silver (Ag) and nitrogen (N) in the bulk of anatase TiO2 are introduced. The geometrical and band structure of perfect TiO2 is modified by doping foreign atoms. Impurity states in the form of In 5p, Ag 4d, N 2p are introduced in the band structure extending its absorption edge towards visible regime. Populated states are noticeable in the band gap of In, Ag, N tri-doped model which might be helpful in step wise migration of electrons between valence and conduction band. The optical absorption is tested via absorption coefficient and imaginary part of the dielectric function. The tri-doped model exhibit enhanced absorption in the visible regime predicting an efficient material for photoelectrochemical applications.