微乳液法合成白光LED NaLu(MO4)2:Eu3+/Eu3+,Tb3+(M=W, Mo)荧光粉

采用微乳液法制备NaLu(WO₄)_2-x(MoO₄)x:8%Eu³⁺(x=0, 0.5, 1.0, 1.5, 2.0)/y%Eu³⁺,5%Tb³⁺(y=1, 3, 5, 7, 9)系列荧光粉.通过X射线衍射(XRD)表征,所制样品的X射线衍射峰与标准卡片PDF#27-0729基本吻合,表明所制的样品为白钨矿结构,属于四方晶系.扫描电镜SEM显示制备的纳米粒子是梭子状的,粒径大约是110 nm.激发发射光谱显示,在Eu³⁺离子掺杂浓度为8%时,NaLu(WO₄)(MoO₄):Eu³⁺发光强度最大.NaLu(WO₄)_2-x(MoO)x :8%Eu³⁺(x=0, 0.5, 1.0, 1.5, 2.0)荧光粉在Mo/W比达到1:1(x=1)时发光强度最大,强烈的红光发射表明该材料可用于白光LED材料.该荧光粉在268、394和466 nm波长光激发下分别发出橙红色、黄色和淡黄色光,可以满足不同光色需要.NaLu(WO)(MoO):y%Eu³⁺,5%Tb³⁺(y=1, 3, 5, 7, 9)荧光粉,随着y值增大,从绿光区(x=0.278, y=0.514)进入白光区(x=0.356, y=0.373), (x=0.278, y=0.313),同时观察到Tb³⁺到Eu³⁺有效能量传递.

Synthesis of White LED Eu3+/Eu3+, Tb3+ Co-doped NaLu(MO4)(M=W, Mo) Phosphor via Microemulsion Method

8%Eu³⁺/y%Eu³⁺,5%Tb³⁺(y=1, 3, 5, 7, 9)codoped NaLu(WO₄)_2-x(MoO4)x (x=0, 0.5, 1.0, 1.5, 2.0) phosphor were prepared via microemulsion method at room temperature. X-ray diffraction (XRD), scanning electron microscopy (SEM) and fluorescence spectroscopy were used to characterize the samples. The XRD of as-prepared samples were in agreement with the PDF#27-0729, showing that sample was the scheelite structure, belongs to the tetragonal crystal system. SEM images showed that the as-prepared particles were shuttle. Particle size was about 110 nm. The critical activator molar concentration (Eu³⁺ in NaLu(WO₄)(MoO₄):Eu³⁺ was 8%. As the Mo content increased, the intensity of emission of Eu3+ activated at wavelength of 394 nm and 466 nm increased and reached a maximum when the relative ratio of Mo/W was 1:1. The intense red-emission of the tungstomolybdate phosphors at near-UV and blue excitation suggested that the material was a potential candidate for white light emitting diode (WLEDs). This phosphor excited by 268, 394 and 466 nm, exhibited orange-red, yellow and pale yellow respectively, meeting the needs of the different light color. In the systems of NaLu(WO₄)(MoO₄):y%Eu³⁺,5%Tb³⁺(y=1, 3, 5, 7, 9) phosphors, with the increase of the doped concentration of Eu³⁺ (y), the emission color of the co-doped NaLu(WO₄)(MoO₄) phosphors can be tuned precisely from green (x=0.278, y=0.514)to white (x=0.356, y=0.373), (x=0.385, y=0.313). At the same time, a very efficient energy-transfer from Tb³⁺ to Eu³⁺ can be observed.