SiN掺杂提高BaMgAl10O17:Eu2+荧光粉光学性能的第一性原理研究

使用基于密度泛函理论的CASTEP软件计算了BAM:Eu²⁺(BaMgAl₁₀O₁₇:Eu²⁺)荧光粉在SiN掺杂前后的能带、态密度、吸收光谱和Mulliken布居．Eu²⁺处于BR位置光吸收更强；SiN掺杂使处于BR位置的Eu²⁺的数量上升，而处于mO位置的Eu²⁺的数量下降，抵消了SiN掺杂降低Eu的态密度对光谱的影响．所以适量掺杂的SiN提高了BAM:Eu²⁺荧光粉的吸收发射光谱强度．Si-N键和Eu-N键的Mulliken布居数分别高于Al-O键和Eu-O键， 说明Si-N键和Eu-N键的共价性分别强于Al-O键和Eu-O键．发光中心Eu²⁺局域结构共价性的增强降低了BAM:Eu²⁺镜面层的活性，这是SiN掺杂提高BAM:Eu²⁺+荧光粉光学稳定性的主要原因．

First-principle Studies on Enhanced Optical Stability of BaMgAl10O17:Eu2+ Phosphor by SiN Doping

Using density functional theory, we studied band structure, density of states, optical proper-ties 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 en-ergy 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 vari-ation 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⁺.