无机材料学报

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伽马辐照对LaBr3:Ce和CeBr3晶体发光的影响

彭晨1, 何伟民1, 贾宇桢1, 宋柏君1, 程瑶1, 范潇宇1, 白庆睿1, 常骏1, 刘波2, 王忠志2, 杨帆1   

  1. 1.南开大学 物理科学学院,天津 300071;
    2.包头稀土研究院,包头 014030
  • 收稿日期:2026-07-14 修回日期:2026-07-28
  • 通讯作者: 杨 帆, 教授. E-mail: fan@nankai.edu.cn; 王忠志, 高级工程师. E-mail: 198322wzz@163.com
  • 作者简介:彭 晨(1997-), 女, 博士研究生. E-mail: 1120220080@mail.nankai.edu.cn
  • 基金资助:
    新型固态照明与显示用稀土发光材料关键制备技术开发(2025Z2633); 国家自然科学基金(12575193); 功能晶体与器件全国重点实验室开放课题(SKLFCD202502SIC)

Influence of Gamma-ray Irradiation on the Luminescence of LaBr3:Ce and CeBr3 Crystals

PENG Chen1, HE Weimin1, JIA Yuzhen1, SONG Baijun1, CHENG Yao1, FAN Xiaoyu1, BAI Qingrui1, CHANG Jun1, LIU Bo2, WANG Zhongzhi2, YANG Fan1   

  1. 1. School of Physics, Nankai University, Tianjin 300071, China;
    2. Baotou Research Institute of Rare Earths, Baotou, 014030, China
  • Received:2026-07-14 Revised:2026-07-28
  • Contact: YANG Fan, professor. E-mail: fan@nankai.edu.cn; WANG Zhongzhi, Senior Engineer. E-mail: 198322wzz@163.com
  • About author:PENG Chen (1997-), female, PhD candidate. E-mail: 1120220080@mail.nankai.edu.cn
  • Supported by:
    Development of Key Preparation Technologies for Rare-Earth Luminescent Materials for Next-Generation Solid-State Lighting and Displays (2025Z2633); National Natural Science Foundation of China (12575193); Funding of State Key Laboratory of Functional Crystals and Devices (SKLFCD202502SIC)

摘要: LaBr3:Ce和CeBr3晶体具有高光产额、快衰减和良好的能量分辨率,广泛应用于γ能谱测量和空间探测等辐射环境,因此有必要研究其服役过程中的辐照损伤效应。目前,关于两种晶体电离辐照后发光行为变化的研究较少。本研究采用γ射线对LaBr3:Ce和CeBr3晶体进行辐照,并结合辐照诱导吸收系数(Radiation Induced Absorption Coefficient, RIAC)谱、光致发光(Photoluminescence, PL)和PL衰减曲线,研究两种晶体辐照前后的发光和衰减动力学变化。结果表明,辐照前,两种晶体均存在Ce3+ 5d→4f跃迁发光和自陷激子(Self-Trapped Exciton, STE)宽带发光,且Ce3+发光谱与STE发光激发谱存在一定重叠,说明可能存在Ce3+发光向STE发光的能量传递过程。PL衰减结果显示,两种晶体在300 nm激发下STE发光衰减时间明显长于450 nm激发下STE发光的本征衰减时间,表明300 nm激发下STE发光衰减过程可能由直接激发STE的快过程和Ce3+发光再激发STE发光的慢过程共同贡献。γ射线辐照后,两种晶体RIAC值均随累积辐照剂量增加逐渐趋于饱和。LaBr3:Ce晶体的STE相对发光强度较辐照前明显增加,且300 nm激发下STE发光的衰减时间延长;而CeBr3晶体辐照后的PL谱形和衰减时间均未出现明显变化。结合RIAC谱分析,LaBr3:Ce晶体在辐照诱导吸收趋于饱和后仍出现STE相对发光增强,说明该现象可能与辐照诱导缺陷局域分布变化引起Ce3+发光向STE发光能量传递过程增强有关;300 nm激发下STE发光衰减时间延长则可能与慢发光过程的相对贡献增加有关。本研究为理解LaBr3:Ce和CeBr3晶体辐照诱导发光行为及其辐照损伤效应提供了实验依据。

关键词: LaBr3:Ce晶体, CeBr3晶体, 辐照损伤, 光致发光, 衰减时间

Abstract: LaBr3:Ce and CeBr3 crystals exhibit high light yield, fast decay, and good energy resolution. They are widely applied in γ-ray spectroscopy and space exploration. Therefore, it is essential to investigate their radiation damage effects. At present, changes in the luminescence behavior of these crystals after ionizing irradiation are not sufficiently studied. In this work, LaBr3:Ce and CeBr3 crystals were irradiated step by step with γ-rays. Radiation induced absorption coefficient (RIAC) spectra, photoluminescence (PL) spectra and PL decay curves were used to investigate the luminescence characteristic and decay kinetics of the crystals before and after irradiation. The results show that both crystals exhibit Ce3+ 5d→4f transition emission and self-trapped exciton (STE) broadband emission before irradiation. The overlap between the Ce3+ emission spectra and the excitation spectra of STE emission indicates that there may be the energy transfer process from Ce3+ emission to STE emission. The PL decay results show that the decay time of STE emission under 300 nm excitation is significantly longer than the intrinsic decay time measured under 450 nm excitation. It suggests that the STE emission under 300 nm excitation may involve two contributions: a fast process from direct STE excitation and a slow process associated with STE re-excitation by Ce3+ emission. After γ-ray irradiation, the RIAC values of both crystals gradually approach saturation with increasing cumulative irradiation dose. The relative STE emission intensity of LaBr3:Ce crystal increases significantly compared with that before irradiation, and the decay time of STE emission under 300 nm excitation is prolonged. In contrast, no obvious changes are observed in the PL spectral shape or decay time of CeBr3 crystal after irradiation. Combined with RIAC analysis, the enhanced STE emission in LaBr3:Ce after saturation of radiation-induced absorption may be related to changes in the local distribution of radiation-induced defects, which enhances the energy transfer process from Ce3+ emission to STE emission. The prolonged STE decay time under 300 nm excitation may be associated with the increased relative contribution of the slow emission process. This investigation provides experimental evidence for understanding the irradiation induced luminescence behavior and radiation damage effects of LaBr3:Ce and CeBr3 crystals.

Key words: LaBr3:Ce crystal, CeBr3 crystal, radiation damage, photoluminescence, decay time

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