First-principles calculation and luminescence property of Eu-x:Si5Al1-xO1+xN7-x green phosphor

Abstract

The crystal and electronic structure of Eu doped beta-SiAlON with various Eu concentrations was calculated by the density functional theory and compared to their luminescence properties. Interstitially doped Eu ion was found near N atoms in the atomic channel paralleled to the [0 0 0 1] axis and the Eu-N distance shortens as Eu concentration increases. The additional states originated from the hybridization of Eu-4f with Si-3p and N-2p. The calculated wavelengths from the energy gap between VBM and extra level were 522.7 and 544.8 nm in the low Eu concentration regions. The calculated results are well agreed with experimental results.