First-principles calculations to identify key native point defects in Sr4Al14O25.

ABSTRACT

This article reports for the first time an in-depth ab initio computational study on intrinsic point defects in Sr4Al14O25 that serves as host lattice for numerous phosphors. Defect Formation Enthalpies (DFEs) and defect concentrations were computed considering the supercell approach for different oxygen atmospheres. The charge transition levels have been determined for several point defects in their thermodynamically stable state and their impact on the electronic structure of the ideal unfaulted material is discussed. Our simulations demonstrated that the formation of most of native point defects is energy intensive under oxygen-rich, -intermediate or -poor synthesis conditions, except for the oxygen vacancies under O-poor atmosphere.