掺Tm^(3+)和Tb^(3+)的LiMgPO_(4)磷光体的发光光谱与能量转移  

Luminescence spectra and energy transfer of Tm^(3+) and Tb^(3+) doped in LiMgPO_(4) phosphors

作　　者：续卓 郭竞渊 熊正烨 唐强 高沐 Xu Zhuo;Guo Jing-Yuan;Xiong Zheng-Ye;Tang Qiang;Gao Mu(School of Electronics and Information Engineering,Guangdong Ocean University,Zhanjiang 524088,China;School of Physics,Sun Yat-Sen University,Guangzhou 510275,China;Institute of intelligent manufacturing,Zhanjiang University of Science and Technology,Zhanjiang 524094,China)

机构地区：[1]广东海洋大学电子与信息工程学院,湛江524088 [2]中山大学物理学院,广州510275 [3]湛江科技学院智能制造学院,湛江524094

出　　处：《物理学报》2021年第16期289-296,共8页Acta Physica Sinica

基　　金：广东省科技计划(批准号:2015A020216020);国家自然科学基金(批准号:11375278);广东海洋大学(批准号:CXXL2019260)资助的课题。

摘　　要：稀土掺杂的LiMgPO_(4)(LMP)磷光体是一种很有前景的辐射剂量计材料,热释光谱技术是研究材料中载流子陷阱和发光中心的有效手段.为研究稀土掺杂LMP的发光机制,用高温固相法研制了LMP:Tm,LMP:Tb和LMP:Tm,Tb磷光体,用线性升温法测量了磷光体的热释光发光曲线和热释光谱,并将之与荧光谱进行了对比分析.实验结果表明:在LiMgPO_4磷光体中,Tm^(3+),Tb^(3+)共掺可使磷光体在300℃左右的热释光显著增强;LMP磷光体的热释光谱中可观测到比一般荧光谱更丰富的Tm^(3+)离子和Tb^(3+)离子的跃迁;Tm^(3+)和Tb^(3+)虽然都可成为发光中心,但Tm^(3+)起主要作用;结合对热释光谱和荧光谱的深入分析,可知磷光体中存在Tb^(3+)→Tm^(3+)的能量转移.LiMgPO_(4)(LMP)phosphor doped with rare earth is a promising radiation dosimeter material.Thermoluminescence(TL)spectroscopy is an effective method to study the carrier traps and luminescence centers in materials.To study the luminescent mechanism of rare-earth-doped LMP phosphors,LMP phosphors doped with Tm and Tb(LMP:Tm,LMP:Tb and LMP:Tm,Tb)are prepared by high temperature solid state reaction.The TL glow curve and TL spectrum of the phosphors are measured by the linear heating method,and compared with the photoluminescence(PL)spectrum.The shape of the TL glow curve of LMP phosphor varies with the doping active impurities,but the TL glow curves can be fitted by seven TL peaks.Double-doping Tm^(3+)and Tb^(3+)in LMP phosphor can enhance the TL intensity of the fifth peak(E~1.39 eV)and weaken the seventh TL peak(E~1.70 eV).By comparing the PL spectra with TL spectra of the phosphors,it can be seen that the TL spectra are more complex than the PL spectra excited by ultraviolet light(l=352 nm).In the TL process,the electrons which are excited to the conduction band release the energy to recombination centers,and the released energy can more effectively excite the rare earth ions from the ground state to excited states,resulting in the more TL emitting peaks than in the the PL process.Although Tm^(3+)and Tb^(3+)can be the luminescent centers in LMP phosphors when Tm^(3+)and Tb^(3+)are doped in LMP simultaneously,Tb^(3+)ions are likely to act as sensitizers in LMP:Tm and LMP:Tb phosphor,and Tb^(3+)ions transfer energy to the low-energy Tm^(3+)ions,which makes the luminescent centers,Tm^(3+)ions,excited to the high-energy state and then de-excited with emitting light.This result is also proved by the fact that the luminescence decay of Tb^(3+)in phosphors increases with Tm^(3+)concentration increasing.The energy transfer through non-radiative transition is more significant at higher temperature.

关 键 词：LiMgPO_4 热释光 荧光 能量转移 

分 类 号：O469[理学—凝聚态物理]