First-principles study of the electronic structure and optical properties of Eu2+–M (M = Mn2+, Mg2+, Li+) co-doped γ-AlON phosphor

Abstract

In our recent work we found γ-AlON:Eu2+ phosphors to hold promise for application in white light-emitting diodes (LEDs). To obtain further insight into Eu2+–M (M = Mn2+, Mg2+, Li+) co-doped γ-AlON, the crystal structure and the electronic and photoluminescence properties of γ-AlON:Eu2+–M (M = Mn2+, Mg2+, Li+) phosphors were studied using first-principle calculations under the framework of density functional theory. Based on the experimental and calculated results, the structure of Eu2+–M (M = Mn2+, Mg2+, Li+) co-doped γ-AlON was established. The calculated results demonstrate that Eu2+ and M (= Mn2+, Mg2+, Li+) can effectively improve the absorption of ultraviolet light by γ-AlON:Eu2+. The absorption coefficient of AlON:Eu2+–Li+ in the ultraviolet blue region of 275–415 nm reached 67,266 cm–1, and the absorption coefficients of AlON:Eu2+–Mn2+ and AlON: Eu2+–Mg2+ at the same doping concentration were 51,219 and 60,575 cm–1, respectively. Our calculations therefore show that the performance of AlON:Eu2+–Li+ is better than AlON:Eu2+–M (M = Mn2+, Mg2+).