Theoretical investigation of thermodynamic and optoelectronic properties of Ce4+ doped SrZrO3 ceramics: A DFT study

Abstract

Theoretical insight into the thermodynamic, structural, electronic and optical properties of SrZr1-xCexO3 (x = 0, 0.037 and 0.125) ceramics is presented using DFT calculations for predicting their potential applications as photocatalysts. The stable incorporation of Ce4+ dopant at Zr site of SrZrO3 is examined in terms of enthalpies of formation and defect formation energies using valid limits of atomic chemical potentials of the species involved in substitutional doping. Our results indicate expansion in the SrZrO3 lattice and decrease of band gap with increasing cerium doping concentration. Significant differences are observed in the electronic and optical properties of SrZr1-xCexO3 ceramics due to different nature of unoccupied Ce-4f states above the Femi level when cerium doping concentration increases from x = 0.037 to x = 0.125. Inclusion of the spin-orbit coupling in our DFT calculations are found to cause splitting of the unoccupied Ce-4f states above Fermi level for high concentration of doping. The trends observed in the structural and electronic properties of SrZr1-xCexO3 ceramics with increasing cerium doping concentration are found to be qualitatively similar for calculations performed without and with the inclusion of spin-orbit coupling. We show that the near UV absorption of SrZrO3 can be considerably enhanced by increasing cerium doping concentration beyond x = 0.037; making Ce4+ doped SrZrO3 potential heterogeneous photocatalysts.