Using density functional theory, we studied band structure, density of states, optical properties and Mulliken population of the pure and SiN doped BaMgAl10O17:Eu2+ (BAM:Eu2+) phosphors. Calculation results showed that the bands of BAM:Eu2+ were of low band energy dispersion, indicating large joint density of states, hence high performance of optical absorption and luminescence. BAM:Eu2+ showed stronger absorption intensity while Eu2+ occupied the BR sites instead of the mO sites. The concentration of Eu2+ at BR sites increased while that at mO sites decreased after Si—N doping. The influence of the variation of Eu2+ distribution on the spectra was stronger than the influence of the decrease of Eu2+ PDOS when SiN concentration was lower than 0.25, therefore the absorption and luminescence intensity of BAM:Eu2+ were enhanced. Mulliken population of Si—N bond was higher than Al—O bond, while that of Eu—N bond was higher than Eu—O bond as well, indicating that Si—N bonds and Eu—N bonds possessed higher covalence than Al—O bonds and Eu—N bonds respectively. The existence of Si—N bonds and Eu—N bonds enhanced the local covalence of Eu2+, hence the optical stability of BAM:Eu2+.
關聯:
Chinese Journal of Chemical Physics 25(4), pp.398-402
