闪烁体Y_2SiO_5:Ce的发光特性  

Luminescence Characteristics of Scintillator Y_2SiO_5:Ce

作　　者：王文静[1] 丁喜峰[2] 孙鑫[1] 朱二旷[1] 李兴元[1] 张红梅[1] 郭得峰[2] 陈海良[1] 

机构地区：[1]燕山大学理学院实验中心,河北秦皇岛066004 [2]燕山大学理学院物理系,河北秦皇岛066004

出　　处：《光谱学与光谱分析》2016年第8期2399-2404,共6页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(61505175);河北省自然科学基金项目(E2013203352)资助

摘　　要：Y_2SiO_5:Ce^(3+)(YSO:Ce)具有高密度、不吸潮以及良好的光输出和快速衰减的特性,是一种重要的闪烁材料。研究采用高温固相法制备Y_2SiO_5:Ce^(3+)+0.2%(YSO:Ce)。在低温及室温下,对闪烁体YSO:Ce的时间分辨发射光谱、激发光谱以及衰减曲线进行了测量和分析。YSO:Ce主要有两类发射,一是晶体的缺陷发射,发射中心在320 nm;二是掺杂的Ce^(3+)的5d→4f发射,发射中心在440 nm。只有当激发能量(E_x)大于材料带隙宽度(E_g)时才能够激发出晶体缺陷发射,对应慢速的激发发射过程,且低温时发射强度较大,当温度升高时有温度猝灭,在室温下时间分辨发射光谱中几乎观察不到晶体缺陷发射。对于发射中心位于440 nm Ce^(3+)的5d→4f能级发射,在60~300 nm范围内能够观察到多个激发峰,其中能量小于材料禁带宽度的激发是属于Ce^(3+)5d能级的直接激发带,对应快速的激发发射过程。在低温时能够观测到发光中心位于392和426 nm分立的发射峰,对应Ce^(3+)的5d→4f(~2F_(5/2),~2F_(7/2))的发射。当温度升高到室温时,光谱宽化,无法观测到分立的发射峰。在温度200和300 K时,当激发光的能量大于带隙宽度,衰减曲线有明显的上升沿,说明有能量传递给Ce^(3+)。Cerium doped Y2SiO5（YSO） is an important scintillator material due to its high density,non-hygroscopic,excellent light output and fast decay time nature,in the paper,Y2SiO5：Ce^3＋0.2%（YSO：Ce） was grown with high-temperature solidphase method.The time-resolved excitation and emission spectra and fluorescent decay curves at low temperature and room temperature（RT） were measured and discussed.There were two types of luminescence,one was the crystal defect emission,the center at 320 nm;the other one was doped Ce^3＋ ions 5d→4f emission,the center at 440 nm.Only when the excitation energy（Ex） was greater than the band gap width（Eg）,the crystal defect emission can be observed corresponding to slow process,and the emission intensity was higher at low temperature.The crystals defect emission was hardly observed in the time-resolved emission spectra when the temperature rose to room temperature because of temperature quenching.Regions from 60～300 nm corresponding to emission due to 5d→4f transitions in the activator Ce^3＋ ions peaks at 440 nm,a plurality of excitation peaks were observed.Among them,the excitation with energy less than 6.1 eV（ExEg） was the direct excitation band belonging to the 5d energy level of Ce^3＋ ions.The corresponding excitation emission was fast process.Two emission peaks centering at 392 and 426 nm were observed at low temperature,corresponding to the Ce^3＋ ion electron transition from the lowest 5d level to the two spin-orbit 4/ ground state of Ce^3＋（^2F5/2,^2F7/2）.With increasing temperature the doublet was thermalized and at RT the emission peak separation cannot be observed.At 200 and 300 K,when the excitation energy（Ex） was greater than the band gap width（Eg）,decay curve had obvious rising edge,which shows that some energy is transmitted to Ce^3＋ ions.

关 键 词：闪烁体 稀土离子 硅酸钇 发射光谱 激发光谱 光谱特性 

分 类 号：O462[理学—电子物理学]