Li^+掺杂Sr_2MgSi_2O_7∶Eu^(2+),Dy^(3+)长余辉材料的发光性能

Luminescent Properties of Li+doped Sr_2MgSi_2O_7∶Eu^(2+),Dy^(3+) Phosphors

采用高温固相法制备Li+掺杂Sr2Mg Si2O7∶Eu2+,Dy3+长余辉材料,对样品进行X射线衍射、扫描电镜、激发光谱、发射光谱、余辉衰减曲线和热释光曲线表征,研究了Li+掺杂对Sr2Mg Si2O7∶Eu2+,Dy3+发光性能的影响。实验结果表明:Li+掺杂对样品激发光谱和发射光谱的峰形、峰位基本没有影响,但是能改善样品的余辉性能。与未掺杂Li+的样品比较,Li+掺杂摩尔分数为2.5%样品的初始发光强度提高了1.5倍,余辉衰减常数提高了1.6倍。通过热释光曲线表征分析陷阱数量并计算了陷阱深度,分析表明,掺杂Li+能增加基质中氧空位的数量,适量增加陷阱深度,从而提高材料的发光性能。

Sr2MgSi2O7∶Eu^2＋,Dy^3＋and Sr2MgSi2O7∶Eu^2＋,Dy^3＋,Li^＋phosphors were prepared by conventional solid state reaction method,and the influence of Li^＋doping on the luminescent properties of Sr2MgSi2O7∶Eu^2＋,Dy^3＋ phosphors was studied. The samples were characterized by X-ray diffraction（ XRD）,scanning electron microscope（ SEM）,photoluminescence（ PL）,decay curves,and thermoluminescence（ TL）. The results indicate that the incorporation of Li^＋ions has no influence on the position of the emission peak which is determined by 4f^7→4f^65d～1of Eu^2＋,while it has relationships with the intensity of the emission and the afterglow. The highest phosphorescent intensity was observed with 2. 5% of Li^＋,and compared with the undoped sample,the phosphorescent intensity and the decay constant were increased by 1. 5 and 1. 6 times,respectively. By the characteristic of TL measurement,the number and the depth of trap level were analyzed. The doping of Li^＋can increase the number of oxygen vacancies and increase the trap depth,so as to improve the afterglow properties of phosphor.