First-principles calculation on the electronic structure and optical properties of Eu2+ doped γ-AlON phosphor

The crystal structure, electronic structure, and optical properties of Eu-doped γ-AlON at various Eu concentrations were obtained from density functional theory. Based on the calculated results, the luminescence properties and mechanism of Eu-doped γ-AlON are discussed. The calculated results demonstrate that AlON:Eu2+ phosphor exhibits a direct band gap, which is advantageous for luminescence. The absorption spectrum of AlON:Eu2+ phosphor has a single intense broad absorption band from 275 to 425 nm with a peak at 355 nm, which is consistent with corresponding experimental excitation spectra. The existence of Eu‒N bonds enhanced the local covalence of Eu2+, hence the optical stability of AlON:Eu2+ phosphor.