Ab-initio calculations of synergistic chromium-nitrogen codoping effects on the electronic and optical properties of anatase TiO2

► Ab-initio calculations were carried out for (Cr, N) codoped TiO2. ► In compensated (Cr, N) codoped models, individual defects bind each other. ► Compensated codoped model has stable structure and better optical properties. ► All doped models shifted the absorption edge of TiO2 towards visible light.