铕掺杂NASICON结构红色荧光粉制备和发光性能

Preparation and Luminescence Properties of Eu3+ Doped NASICON-based Red Phosphors

采用高温固相法在空气气氛中制备了具有NASICON结构的Eu^3+掺杂Na3Zr2Si2PO12:Eu^3+红色荧光粉。利用X射线衍射、漫反射光谱、荧光光谱、荧光寿命衰减曲线以及量子效率系统研究了该样品的晶体结构及荧光性能。结果表明,样品XRD图中不含明显的杂峰,表明在实验浓度范围内Eu^3+的掺杂没有改变基质的晶体结构,样品为单相。合成过程中,需要对样品多次压片烧结,才能获得较好的单相。在近紫外光激发下,样品能发出618 nm红光,荧光强度最大对应的Eu^3+的掺杂摩尔分数是24%。根据Rexter理论分析,浓度猝灭源于Eu^3+离子之间的电四极-电四极相互作用。样品在室温下的最高内量子效率和外量子效率分别是61%和15%,荧光衰减的寿命范围在2.08~2.84 ms。样品Na2.76Zr2Si2PO12:0.24 Eu^3+在150℃时内量子效率约为50%,表明样品具有良好的热稳定性。将样品Na2.76Zr2Si2PO12:0.24 Eu^3+与394 nm波长的紫外芯片封装成LED灯,显色指数达到75.6. Eu^3+掺杂Na3Zr2Si2PO12有望作为一种新型红色荧光粉用于近紫外激发白光LED。

In order to explore a new type of red phosphor, Eu^3+ doped NASICON structure-based phosphors Na3Si2PO12:Eu^3+ were prepared by high temperature solid phase method in air atmosphere. The crystal structure and optical properties of the samples were systematically studied by X-ray diffraction, diffuse reflectance spectroscopy, fluorescence spectroscopy, fluorescence lifetime decay curve and quantum efficiency. The results demonstrate that XRD patterns confirm the pure phase of Na3 r2Si2PO12: Eu^3+ phosphor as obtained, since not any excess peaks can be found in XRD patterns and Eu^3+ doping does not change the crystal structure of Na3Zr2Si2PO12 host. Eu^3+ doping ensures the red emission at 618 nm under the excitation at UV light. An optimized doping concentration of Eu^3+ is 24%, while the quenching mechanism beyond the doping concentration at 24% is electric quadrupole-electric quadrupole interaction according to Rexter Theory. The highest internal and external quantum efficiencies are 61% and 15%, respectively;furthermore, the luminescence quenching can be suppressed even at150 ℃, depending on a high internal quantum efficiency about 50%. It is packaged into an LED lamp with a color rendering index of 79.4. Therefore, Eu^3+ doped Na3Zr2Si2PO12 is expected to be used as a new type of red phosphor for white LEDs.