Optical properties of Pr and Eu-doped SrAl12O19: A theoretical study

This paper describes a computational study of extrinsic defect and optical properties of SrAl12O19 induced by trivalent rare earth dopants. Solution energies for a range of possible doping mechanisms are calculated, and predictions made of doping sites and charge-compensation schemes. Atomistic modelling is used to calculate the symmetry and detailed geometry of the dopant ion-host lattice system, and this information is then used to calculate the crystal field parameters. It is found that the preferred doping mechanism for Pr is a substitution at Sr2+ sites, with charge compensation by anti-site and for Eu is a substitution at the Al3+ site. Crystal field parameters have been calculated and the results discussed in terms of optical properties of the doped systems. Bkq values indicate that the site symmetry is D2h. The transition levels are then calculated for the Pr3+ and Eu3+-substituted material, and comparisons made with experimental results have a good agreement.