Theoretical studies on the electronic structure and optical properties of NaTaO3 doped with different concentrations of cerium and nitrogen

In this paper, density functional theory is used to investigate the effect of single doping and co-doping of Ce and N atoms at different concentrations on the electronic structure and optical properties of NOT system. The calculation results reveal that Ce concentration of 0.375 at% provides the best stability in the co-doped systems. Doping elements have a significant influence on the chemical properties of NOT and can lead to lattice distortion, which is beneficial for the separation of photogenerated electron-hole pairs. After doping, the band gap of the system is reduced. Consequently, the energy required for the electronic transition from valence band to conduction band is reduced, which causes a red shift in the absorption band edge. The absorption spectrum of the co-doped system appears in the visible range. When the Ce concentration in the co-doped system is 0.125 at% and 0.25 at%, a stronger absorption peak appears in the visible range, indicating that these two systems have the best response to visible light.