Tm3+掺杂SrAl2O4:Eu2+的光激励和热释光性能

通过高温固相法制备出Sr_{0.98-xAl2O4:0.02Eu²⁺,xTm³⁺(x=0,0.01,0.02,0.03,0.04,0.05)系列样品,并对其光激励和热释光性能进行了研究。在SrAl2O4:Eu²⁺原有陷阱能级结构的基础上,通过Tm³⁺的掺杂引入了更深的陷阱TB,并增加原有陷阱TA浓度,进而优化了材料的光存储容量及光激励特性。对比研究了系列样品的初始光激励发光强度和热释光强度随着Tm³⁺掺杂量的变化规律,证实陷阱TB为光激励发光提供了有效俘获中心。当Tm³⁺的掺杂摩尔分数x=0.03时,材料中的陷阱TB的浓度达到最高值,同时光激励发光强度最大。对比Tm³⁺共掺前后热释光图谱,通过Chen's半宽法计算出了引入陷阱TB的陷阱深度。实验结果证实材料中TB的浓度对其光激励发光性能起着决定性的作用。在980 nm激发下,由深陷阱TB释放出来的电子可以再次被浅陷阱TA俘获,这种浅陷阱TA的再俘获效应在光激励发光过程中表现为光激励余辉现象。}

Photo-stimulated and Thermo Luminescence Properties of Tm3+ Doped SrAl2 O4:Eu2+ Phosphors

A series of electron capture materials Sr_0.98-xAl₂O₄:0.02Eu²⁺,xTm³⁺(x=0, 0.01,0.02, 0.03, 0.04, 0.05) were synthesized by a conventional solid-state reaction method. The deeper new trap (T_B) was introduced into the SrAl₂O₄:Eu²⁺ phosphor lattice by the co-dopant of Tm³⁺ ions to optimize the properties of the ETM phosphor. Meanwhile, the trap concentration of intrinsic shallow trap (T_A) was increased. The properties of photo-stimulated luminescence (PSL) and thermoluminescence (TL) in the series samples were investigated. It is found that T_B is responsible for the performance of PSL. The most efficient initial PSL can be obtained when the co-doping mole fraction of Tm³⁺ is 0.03, which keeps the correspondence with the strongest TL intensity of T_B. Besides, the phosphors show a PSL afterglow under 980 nm stimulation, which can be ascribed to the re-trapping of T_A as the electrons firstly excited from T_B will be re-trapped by the empty T_A to generate the PSL afterglow.