调控ZnGa_(2)O_(4):Cr^(3+),Li^(+)近红外长余辉材料的陷阱缺陷改善余辉性能

Near-infrared Persistent Luminescent Phosphor of ZnGa_(2)O_(4):Cr^(3+),Li^(+):Defect Trap Regulation for Improvement of Afterglow

采用高温固相法合成了ZnGa_(2)O_(4):0.005Cr^(3+),xLi^(+)近红外长余辉材料。采用XRD、SEM、TEM、Uv-Vis、PL/PLE等对样品进行表征,系统研究了Li^(+)的掺入对ZnGa_(2)O_(4):Cr^(3+)微观结构和性能的影响。结果表明:材料在紫外光或者可见光的激发下,在693 nm处呈现近红外(Cr^(3+)的^(2)E→^(4)A_(2)跃迁)长余辉发射。掺杂Li^(+)提高可见光的激发效率,当x从0增至0.07时,407 nm和555 nm处的激发峰强度分别增加了114%和120%。Li^(+)的掺入还对ZnGa_(2)O_(4):Cr^(3+)的陷阱类型和数量产生影响,其中,x=0.07的样品具有较多数量的深陷阱,加热时可释放出高强度的余辉,在光信息存储领域具有良好的应用前景。

Near-infrared(NIR)persistent luminescence phosphors,ZnGa_(2)O_(4):Cr^(3+),xLi^(+),were synthesized by using a high-temperature solid state reaction method.The phosphors were characterized by using XRD,SEM,TEM,Uv-Vis,PL/PLE,PLE/PL,in order to examine the influence of Li^(+) on their microstructure and properties.The phosphors output NIR afterlow(^(2)E→^(4)A_(2) transition of Cr^(3+))upon UV or visble excitation.Incorporation of Li^(+)enhanced the efficiency of visible light excitation,thus lading to an enhancement in NIR emission.As the x value was increased from 0 to 0.07,the excitation intensities of 407 nm and 555 nm were increased by 114% and 120%,respectively.The type and concentration of traps of ZnGa_(2)O_(4):Cr^(3+)were significantly dependent on the incorporation of Li^(+).The sample with x=0.07 had a high concentration of deep traps and thus exhibited high-intensity afterglow through recycle heating,indicating potential application in optical information storage.