MgAl2O4:Ce荧光粉辐照合成及发光机理研究

通过伽马射线辐照辅助聚丙烯酰胺凝胶法合成了MgAl2O4和MgAl2O4:Ce荧光粉。通过X射线粉末衍射仪(XRD)、透射电子显微镜(TEM)、紫外可见分光光度计和荧光分光光度计研究了MgAl2O4:Ce荧光粉的晶体结构、表面形貌、光学性质和发光性质;基于实验所获得的结果,分析了纳米级MgAl2O4:Ce荧光粉的发光机理。实验结果表明:采用伽马射线辐照辅助聚丙烯酰胺凝胶法制备纯相MgAl2O4和MgAl2O4:Ce荧光粉的结晶温度要比传统聚丙烯酰胺凝胶法低100℃左右;MgAl2O4:Ce荧光粉的平均颗粒尺寸为14 nm,Ce离子掺杂后导致样品颗粒细化;Ce离子的掺入,降低了MgAl2O4的能带值,改善了其颜色性质和发光性质;当采用275 nm的光去激发MgAl2O4:Ce荧光粉时,获得了425 nm和464 nm的蓝光发射。通过能量传递原理分析认为,杂质缺陷(Ce3+)在整个发光过程中扮演了重要角色。MgAl2O4:Ce作为一种抗辐射能力强的荧光粉,在空间照明领域具有很好的应用前景。

Irradiation synthesized and photoluminescence mechanism of MgAl2O4:Ce phosphor

MgAl₂O₄ and MgAl₂O₄:Ce phosphors were successfully synthesized through a gamma-ray irradiation assisted polyacrylamide gel route.The crystal structure,surface morphology,optical and photoluminescence properties of MgAl₂O₄:Ce phosphors were studied by X-ray powder diffraction（XRD）,transmission electron microscopy（TEM）,ultraviolet-visible spectrophotometer and fluorescence spectrophotometer.Based on the experimental results,the photoluminescence mechanism of nanoscale MgAl₂O₄:Ce phosphors was analyzed.Experiment result showed that the crystallization temperature of MgAl₂O₄ and MgAl₂O₄:Ce phosphors synthesized by a gamma-ray irradiation assisted polyacrylamide gel route was lower about 100 ℃ than that of the conventional polyacrylamide gel route.The mean particle size of the MgAl₂O₄:Ce phosphor was 14 nm.Cerium doping MgAl₂O₄ decreased the particle size and E_g value,improved the colour and photoluminescence properties of MgAl₂O₄.Two blue emission peaks at 425 nm and 465 nm were observed for the MgAl₂O₄:Ce phosphor when the excitation peak was 275 nm.The impurity defect（Ce³⁺） played a crucial role in the luminescence process on the basis of the energy transfer mecha nism.The MgAl₂O₄:Ce phosphor can be used as a promising radiation resistance phosphor for space lighting field.