采用高温固相法制备了LiGd(WyMo1-y)2O8-x/2Fx∶0.4Eu3+ (x=0~1,y=0~1)系列白光LED用红色荧光粉。通过扫描电子显微镜、X射线衍射仪、红外光谱仪、荧光光谱仪对荧光粉的形貌、结构、光学性能进行了表征。结果表明, Eu3+、F-和WO2-4的掺杂没有改变LiGd(MoO4)2的四方晶系白钨矿结构; F-和WO2-4最佳掺杂量分别为x=0.6, y=0.4。在396 nm激发下, LiGd(W0.4Mo0.6)2O7.7F0.6∶0.4Eu3+的发光强度比未掺杂样品提高了60%, 量子效率可达66.23 %。当温度升高至100 ℃时, 样品的发射强度降为25 ℃时的76.6%。在460 nm激发下, 样品的最强窄带发射峰位于617 nm处, 归属于5D0→7F2跃迁, 色坐标为(0.649 9, 0.346 3)。5D0能级的荧光寿命曲线遵循单指数规律衰减, 随着F-掺杂浓度的增加, 5D0能级的荧光寿命不断增加, 归因于低声子能量的F-掺入有效减小了能量的无辐射跃迁概率。所制备的LiGd(W0.4Mo0.6)2O7.7F0.6∶0.4Eu3+荧光粉有望应用于白光LED。

LiGd(WyMo1-y)2O8-x/2Fx∶0.4Eu3+ red phosphors with different F- and WO2-4 doping concentrations for white LEDs were synthesized by the solid state reaction method. Morphology, structure, optical properties of LiGd(WyMo1-y)2O8-x/2Fx∶0.4Eu3+ phosphors were studied by scanning electron microscope(SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and fluorescence spectrometer. The results show that the samples doped with Eu3+, F- and WO2-4 have tetragonal scheelite structure. The optimum doping content of F- and WO2-4 is x=0.6 and y=0.4 , respectively. Under 396 nm excitation, the maximum emission intensity of LiGd(W0.4Mo0.6)2O7.7F0.6∶0.4Eu3+ in which the quantum efficiency is 66.23% is higher than 60% in comparison with LiGd(MoO4)2∶0.4Eu3+. When the temperature turned up to 100 ℃, the emssion intensity of LiGd(W0.4Mo0.6)2O7.7F0.6∶0.4Eu3+ is 76.6% of the initial value at 25 ℃. Under 460 nm excitation, intense red emissions corresponding to 5D0→7F2 transitions of Eu3+ are observed. The chromaticity coordinates of LiGd(W0.4Mo0.6)2O7.7F0.6∶0.4Eu3+ phosphors are (0.649 9, 0.346 3). Decay curve of 5D0 state for as-prepared samples fits the single order exponential behavior, the lifetime of 5D0 increases with the increasing of F- doping concentration, which is due to the reduction of non-radiative transition probability results from the low phonon energy property of F-. LiGd-(W0.4Mo0.6)2O7.7F0.6∶0.4Eu3+ phosphors are suitable for the white LEDs.1000-7032(2016)10-1217-06 1000-7032(2016)10-1203-10