花状NaLa(MoO_4)_2∶Eu^(3+),M(M=Gd^(3+),Ti^(4+))红色荧光粉的水热合成及发光性能

Hydrothermal Synthesis and Luminescent Properties of Flower-like NaLa( MoO_4)_2∶ Eu^(3+),M( M =Gd^(3+),Ti^(4+)) Red-emitting Phosphors

以乙二醇和水的混合溶液为溶剂,采用水热法合成了花状的NaLa(MoO4)2∶Eu3+红色荧光粉。通过X射线衍射仪、扫描电子显微镜、荧光分光光度计等手段对产物进行了分析和表征。结果表明:产物NaLa(MoO4)2∶Eu3+属于四方晶系白钨矿结构。样品分散性好,粒度均匀,呈花状结构。样品的激发光谱分为两部分:位于250~350 nm的宽激发带归属于Eu-O,Mo-O之间的电荷迁移;350~500 nm的系列尖锐峰归属于Eu3+的f-f跃迁。样品的发射光谱中主发射峰位于615 nm处,归属于Eu3+的5D0→7F2电偶极跃迁。此外,共掺杂适量的Gd3+或Ti4+能够有效敏化Eu3+的发光,明显增强了615 nm的红光发射。

Using mixed solution of ethylene glycol and water as solvent,Eu^3＋doped flower-like NaLa（ MoO4）2phosphors were prepared by the hydrothermal process. The products were characterized by Xray diffraction,scanning electron microscope,and fluorescence spectrophotometer. The results show that as-synthesized NaLa（ MoO4）2∶ Eu^3＋are of tetragonal scheelite structure. The particles are dispersing well,regular in morphology and flower-like. The excitation spectra consist of two parts,one is a strong broad band from 250 nm to 350 nm,which is responsible for the charge-transfer band of Mo-O and EuO; the other is a series of sharp lines in the range of 350-500 nm due to f-f transitions of Eu^3＋. The strongest emission peak of the sample is at 615 nm which corresponds to the^5D0→^7F2transition of Eu^3＋.Furthermore,the co-doped Gd^3＋or Ti^4＋can efficiently sensitize the luminescence of Eu^3＋. The redemitting at 615 nm is enhanced obviously.