Cr^3＋和Si^4＋共掺对LiGa5O8近红外长余辉材料发光性能的影响

Influence of Si^(4+)-doped on persistent luminescence of LiGa_5O_8:Cr^(3+) near-infrared phosphors

高温固相法合成了共掺Si^(4+)的LiGa_5O_8:Cr^(3+)长余辉材料,采用X射线衍射、荧光光谱、余辉发射光谱、余辉衰减曲线和热释光对样品分别进行了表征,并分析了Si掺杂对LiGa_5O_8:Cr^(3+)发光性能的影响。结果表明,所合成的LiGa_5O_8:Cr^(3+),Si^(4+)材料能产生近红外长余辉发射,主发射峰位于717nm,归属于Cr^(3+)的~2 E→~4A_2跃迁,共掺Si^(4+)能显著提高余辉性能。掺杂浓度为0.25时,样品的初始发光强度提高了3倍,余辉性能最佳,余辉持续时间超过30h。热释光曲线表明,共掺Si^(4+)离子可增加有效陷阱数量,从而改善材料的余辉发光性能。

A series of LiGa5-x SixO5 ：0. 5%Cr3＋ （x=0,0. 1,0. 25,0.5,0. 75） near-infrared persistent phosphors were successfully prepared by the high-temperature solid state reaction method in air. The lu- minescence properties and the afterglow behaviors of phosphors were investigated in details. The results indicate that these phosphors exhibit near -infrared long afterglow emission centered at 717 nm due to the 2 E→4A2 transition of Cr3＋ ions. The incorporation of Si4＋ significantly improves the persistent lu- minescence performance of phosphors. The optimized persistent performance and the strongest lumines- cence intensity could be obtained when the doping content of Si4＋ in LiGa5 08 ：Cr3＋ is experimentally a- bout 0.25. The afterglow can last for approximately about 30 h. Thermoluminescence spectra indicate that the incorporation of Si4＋ contributes to the formation of defects and increases the number of traps, thus improving the persistent luminescence properties of phosphors.