LiMgPO_4:Tm,Tb的热释光和光释光陷阱参数

采用高温固相法合成了LiMgPO_4:Tm,Tb粉末样品,测定了热释光陷阱参数激发能E和频率因子s.用脉冲退火和多次退火方法研究了其光释光陷阱参数E和s,并与用多速法得到的热释光的结果进行了比较.对不同β射线剂量照射的样品发光曲线的研究表明,300°C高温峰属于一级动力学发光峰.通过对热释光和光释光陷阱的相关性研究表明,经200°C预热的热释光信号(对应于300°C高温峰)和光释光信号很有可能来自于同一深度的陷阱.     

(Lu,Y)2SiO5∶Ce3+与SrSO4∶Dy3+材料低温热释光及其测试仪器的研究

为了分析材料在低温下的陷阱能级,获得更多有关缺陷结构的信息,研制了一套由STM32微控制器为核心的低温热释光发光谱测量系统。设计了低温样品室,采用液氮冷却样品;STM32通过控制加热电流,实现样品以恒定速率升温,从而获得低温热释光发光曲线或三维热释光谱。温度测量范围为85~400 K,升温速率范围为0.1~10 K/s。设计了由STM32控制X射线及紫外光源的驱动电路,用于样品的激发。采用高灵敏度CCD实现对三维热释光谱的测量,采用单光子计数器获取二维热释光发光曲线。利用该系统测试了（Lu,Y）₂SiO₅:Ce³⁺（LYSO:Ce³⁺）单晶闪烁体与SrSO₄:Dy³⁺粉末样品的热释光谱及辐射发光光谱。观察到LYSO:Ce³⁺在108,200,380 K左右的热释光峰,发光波长位于390~450 nm之间,是明显的宽带峰。在低温下由于基质的自陷激子（STE）发射所形成的发射峰在166 K时发生猝灭。在309 K时,Ce³⁺发射峰展宽为单一发射峰;SrSO₄:Dy³⁺发光峰温度为178,385 K,发光波长由Dy³⁺离子的能级跃迁决定,在480,575,660,750 nm处呈现窄带发光峰。结果表明,系统人机交互界面友好,实验数据可靠,智能化程度高,操作简单。     

(Zn,Cd)S∶Cu,Cl发光材料的热释发光

在ZnS中分别掺杂质量分数为5%、7%、10%、15%、20%的CdS,得到一系列(Zn,Cd)S∶Cu,Cl粉末电致发光材料样品。测量样品材料的热释发光曲线,发现五个样品在温度-180～-20℃范围内均有两个明显的热释发光峰。CdS含量的变化对材料中陷阱的种类和陷阱深度没有明显的影响,两个峰值温度在-150℃和-50℃附近。Cd离子的掺入改变了材料较深陷阱中载流子的浓度,随着CdS量的增加,使得在-50℃的热释发光峰的相对强度增大。通过测量样品的发光光谱和发光亮度,发现随着CdS含量的增加,样品材料的发射光谱向长波方向移动,发光亮度呈下降的趋势。     

(Zn,Cd)S：Cu,Cl发光材料的热释发光

在ZnS中分别掺杂质量分数为5%、7%、10%、15%、20%的CdS,得到一系列(Zn,Cd)S:Cu,Cl粉末电致发光材料样品。测量样品材料的热释发光曲线,发现五个样品在温度-180～-20℃范围内均有两个明显的热释发光峰。CdS含量的变化对材料中陷阱的种类和陷阱深度没有明显的影响,两个峰值温度在-150℃和-50℃附近。Cd离子的掺入改变了材料较深陷阱中载流子的浓度,随着CdS量的增加,使得在-50℃的热释发光峰的相对强度增大。通过测量样品的发光光谱和发光亮度,发现随着CdS含量的增加,样品材料的发射光谱向长波方向移动,发光亮度呈下降的趋势。     

热释光和光释光发光谱的测量

介绍了自行研制的计算机化热释光和光释光三维光谱测量装置的系统结构及其工作原理.在计算机的控制下,通过精密加热器或激发光源以热激发或光激发的方式使样品发光.从样品发出的光经过光路和光栅分光系统后,形成光谱,被高灵敏度的CCD采集,再将光谱图像模拟信号变为可以直接用计算机进行数据处理的数据信号.波长范围200~800nm,波长分辨率优于2nm,人机界面友好,操作方便.利用热释光和光释光三维光谱测量装置测量了SrSO₄:Eu(0.1%,摩尔分数)和CaSO₄:Eu(0.1%,摩尔分数)的光释光发光谱和热释光发光谱,得到SrSO₄:Eu的光释光发光波长与热释光发光波长均为375nm,而CaSO₄:Eu的光释光发光波长与热释光发光波长均为385nm,说明热释光和光释光具有相同的发光中心,均来自于Eu²⁺的能级跃迁.同时在CaSO₄:Eu的热释光发光谱中还观察到了Eu³⁺的发光.与二维发光曲线相比较,通过对三维热释光和光释光发光谱的研究,可以得到更丰富的信息,这有助于对热释光和光释光发光机制进行更深入的研究.     

热释光谱研究长余辉发光材料的陷阱能级

介绍了热释光剂量计和热释光的基本原理。通过测量长余辉发光材料的热释光谱,并采用一阶动力学近似,可以量化分析长余辉发光材料中的陷阱能级的深度、电荷密度等参数,并可以讨论陷阱能级与长余辉性能的关系,深入理解长余辉过程。     

SrSO4:Eu磷光体的光释光特性

研究了通过掺杂得到的SrSO4:Eu(0.1mol%)的粉末样品的光释光(OSL)特性.用90Sr的β射线辐照0.116-1.16kGy后,测定了恒定光源激发的光释光发光曲线(CW-OSL)和线性光源激发的光释光发光曲线(LW-OSL),对发光曲线分析均得到了四种陷阱成分.采用复合作用响应函数得到SrSO4:Eu辐射剂量响应为线性-亚线性.测量了温度对OSL信号的影响,结果表明OSL信号的温度稳定性很好,最灵敏读出温度约为180℃,说明这时OSL信号来自热激发和光激发的共同作用.用60Coγ辐照100Gy后,测量了热释光(TL)三维光谱,确定了发光波长主要位于375nm,可以确定这是来自于Eu2+能级跃迁的发光.     

SrSO4:Eu磷光体的光释光特性

研究了通过掺杂得到的SrSO4:Eu(01mol%)的粉末样品的光释光(OSL)特性.用90Sr的β射线辐照0116—116kGy后，测定了恒定光源激发的光释光发光曲线(CW-OSL)和线性光源激发的光释光发光曲线(LW-OSL)，对发光曲线分析均得到了四种陷阱成分.采用复合作用响应函数得到SrSO4:Eu辐射剂量响应为线性-亚线性.测量了温度对OSL信号的影响，结果表明OSL信号的温度稳定性很好，最灵敏读出温度约为180℃，说明这时OSL信号来自热激发和光激发的共同作用.用60Coγ辐照100Gy后，测量了热释光(TL)三维光谱，确定了发光波长主要位于375nm，可以确定这是来自于Eu2+能级跃迁的发光. 关键词： 光释光 热释光 SrSO4:Eu     

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

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。     

CaSO4∶Eu磷光体的热释光特性研究

用热释光三维发光谱仪和蓝色滤光片的热释光仪测定了CaSO4:Eu2+的辐照后的发光曲线,得到峰温为107和144℃波长390nm的发光峰.辐照50d后,107℃发光峰已衰退,发光曲线呈现144℃单个发光峰.经一级力学方程式拟合得到的激活能E=(1.02±0.03)eV与初始升温法(1.07±0.01)eV和峰形法(1.02±0.01)eV的非常符合.用通用级动力学模型拟合发光曲线,得到陷阱能级E=(1.04±0.01)eV,频率因子s=(2.07±0.8)×1012s-1和动力学级数b=1.05±0.02 关键词： CaSO4∶Eu 剂量响应 动力学参量 热释光     

蓝色长余辉材料CaAl_2O_4∶Eu~(2+),Li~+的发光性质

采用高温固相法制备了CaAl_2O_4∶Eu~(2+),Li~+发光材料,并讨论了掺杂Li+对CaAl_2O_4∶Eu~(2+)发光性质的影响。X射线衍射(XRD)和PL测试分析表明,在CaAl_2O_4∶Eu~(2+)中掺入Li~+后,Eu~(2+)的发光有一定的增强,而余辉时间则延长了4倍左右。通过热释光谱测量,分析了其陷阱能级的数量并估算了陷阱能级深度。结果表明,掺杂Li~+会在发光离子周围产生更多的电子陷阱,使陷阱的密度和深度增加,从而提高荧光粉的余辉性能。     

Simultaneous determination of trap depth and the ratio of the rate of recombination to that of capture from thermo-luminescence

Thermo-luminescence (TL) is a kind of luminescence decay measured with varying temperature. In the process of TL the decay parameter itself involves the temperature effect of traps. Thus the trap depth is inseparable from the decay parameter. There are two separate peaks in the TL curve of ZnS:Cu,Co if the measurement starts from liquid nitrogen temperature. In the experiment we started from zero Celsius temperature to isolate the deeper traps. We have proposed and realized three methods for simultaneous determination of trap depth and decay parameter based on the quasi-equilibrium model and experimental data. If we treat the case of kinetic order \alpha =1 as \alpha =2, the error might be as large as 100%.     

Effect of annealing temperature on determining trap depths of quartz by various heating rates method

The aim of this study is to determine the trap parameters (trap depth E, frequency factor s) of quartz using various heating rates method and also to investigate the effect of annealing temperature on determining trap depths. The method is based on the positions of the thermoluminescence peaks, obtained from the change in temperature of the peak at maximum caused by changing the heating rate at which the sample is measured. In the present work, powder quartz samples were annealed first at different temperatures before irradiation. Then samples irradiated to different doses were measured with a TL reader at different heating rates and the glow curves were recorded. In order to calculate the trap depth E and the frequency factor s, the glow parameter T_m was determined experimentally from the glow curve by measuring the shift of the maximum peak temperature depending on heating rate β. The calculation of trap parameters was repeated for each annealing temperature. Then the effect of annealing temperature on trap depths calculated by the various heating rates method was evaluated.     

聚集态和陷阱对交联聚乙烯真空沿面闪络特性的影响

研究了半结晶聚合物交联聚乙烯的聚集态和陷阱等对真空沿面闪络特性的影响.交联聚乙烯(XLPE)在135℃下恒温10min后,分别经过-56℃,-25℃淬火处理,自然降温,或1℃/min,0.5℃/min慢速降温等热处理过程,测量了热处理后试样的电气性能、显微结构、陷阱分布和真空中的沿面闪络特性.实验结果表明,与未热处理试样相比,热处理试样的直流闪络电压最高提高了76%,脉冲闪络电压最高提高了19%.认为热处理改变了XLPE试样的聚集态和陷阱,从而提高了XLPE试样的真空沿面闪络性能,提出了可以通过控制半结晶聚合物的聚集态和缺陷结构提高其真空沿面闪络性能.     

ZnSe:Al发光光谱的研究

本文用热扩散的方法在Zn饱和蒸气压下,把Al掺杂到高纯ZnSe单晶中,通过77K下的光致发光光谱研究了Al杂质的发光行为,讨论了施主一受主对发射强度、自激活中心发射强度随掺杂温度的变化规律以及与Zn饱和蒸气压的关系.本文首次报道了在300℃～900℃温度范围内进行Al掺杂的ZnSe的发光规律.     

波长扫描极值解调法实现光纤光栅应变和温度传感的测量

本文用可编程调谐光纤光栅环行腔激光器作扫描光源,采用波长扫描极值传感解调法对光纤光栅应变及温度进行了测量。应变测量范围为±2440με,灵敏度为0.016step/με;温度测量范围达608℃,灵敏度为0.13step/℃。     

On luminescence stimulated from deep traps using thermally-assisted time-resolved optical stimulation in α-Al2O3:C

We report a study of charge transfer mechanisms of electrons stimulated optically from very deep traps, also known as donor traps, in α-Al₂O₃:C. The investigations were carried out using thermally-assisted time-resolved optical stimulation, thermoluminescence and by way of residual thermoluminescence from the main electron trap. When the charges are optically stimulated from the deep traps, they are redistributed via the conduction band to the main electron trap and the shallow trap from where they are optically or thermally released for recombination at luminescence centres. The luminescence is strongly quenched at high measurement temperature as evident by very short luminescence lifetimes at these temperatures. The main peak due to residual thermoluminescence is located at a higher temperature than the conventional main peak.     

温度对稀土离子掺杂ZBLAN玻璃上转换发光的影响

研究了Er3+,Pr3+和Yb3+共掺杂ZBLAN玻璃在960nm激光泵浦下的上转换发光的温度特性.温度变化范围为室温到300℃.结果表明Pr3+离子的发光强度随温度的增加,先增加;达到极大后,随温度的增加下降.Er3+发光强度随温度增加单调下降.     

Kinetics of Relaxation of Stored Light Sums in Silver Chloride

Experimental investigation of the time and temperature dependences of the process of relaxation of excited silver chloride has been carried out by the method of a photostimulated burst of luminescence. It is found that the relaxation process can be divided into two components, the rates of which differ by an order of magnitude. The activation energies of these processes of 0.03 and 0.06 eV correspond to the thermal ionization energies of electrons from shallow traps. Thermally activated relocalization of charges from shallow to deep traps in the process of relaxation has been revealed. The depth of a corresponding trap appeared equal to 0.17 eV. A model of a crystal phosphor has been suggested that contains five levels in the forbidden band: a hole center of recombination (luminescence), a deep electron trap, two shallow electron traps located at a depth of 0.03 and 0.06 eV from the bottom of the conductivity band, and a hole trap located at a height of 0.17 eV from the valence band top. Within the framework of this model, we can qualitatively explain the time and temperature dependences of stored light sums. We have shown the possibility of applying the method of a photostimulated burst of luminescence to investigation of the processes of relaxation of electron excitations in crystals to establish the relaxation mechanisms.