LED用红色发光材料Li_3Ba_2Ln_(3-x)Eu_x(MoO_4)_8的制备及性能

Preparation and Luminescence of Red Light-emitting Phosphors Based on Li_3Ba_2Ln_(3-x)Eu_x(MoO_4)_8 by Sol-gel Method

采用溶胶-凝胶法合成了发光二极管(LED)用的系列红色荧光粉Li3Ba2Ln3-xEux(MoO4)8(Ln=La,Gd,Y)。利用差热-热重(TG-DTA)分析和粉末X射线衍射(XRD)测定了其最佳合成温度和不同温度下所得样品的结构,发现所有样品均具有单斜结构;采用荧光光谱对所得荧光粉发光性能进行了表征,发现在相同条件下所得样品的发光强度顺序为:Li3Ba2Y2.8Eu0.2(MoO4)8>Li3Ba2Gd2.8Eu0.2(MoO4)8>Li3Ba2La2.8Eu0.2-(MoO4)8。它们在395nm和465nm的激发光源激发时均有强的吸收,与LED芯片发射波长相匹配。同时分析了柠檬酸及分散剂聚乙二醇(PEG-10000)的用量、Eu3+离子的浓度以及焙烧温度等因素对荧光粉发光性能的影响。

A novel red light-emitting phosphors of Li3Ba2Ln3-xEux （MoO4 ）8 were synthesized by sol-gel method. According to X-ray diffraction, the materials belongs to monoclinie system. The structure and luminescent properties of these phosphors were investigated by emission and excitation spectra in details. The main emission peak of the samples is at 616 nm. Effect of the dosage of citric acid and polyethylene glycol and the activator concentration on the crystal structure, morphology and luminescent properties were investigated by using XRD, SEM. These results showed that this phosphor can be effectively excited by ultraviolet （UV） （395 nm） and blue （465 nm） light, matching the output wavelengths of ultraviolet or blue LED chips. Integrated emission intensity of Li3Ba2Y2. 8 Eu0.2 （MoO4 ）8 is the strongest in the series of the Li3 Ba2Ln3-xEux （MoO4 ）8 （Ln = La, Gd, Y） phosphors. The Li3Ba2Ln3-xEux （MoO4） 8 （Ln = La, Gd, Y） phosphors might be a better candidate for solid state lighting application.