Dy<sup>3+</sup>对Tb<sup>3+</sup>激活硅酸盐氟氧闪烁玻璃发光性能的影响

doi:10.3964/j.issn.1000-0593(2019)05-1412-08

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摘要：采用高温熔融法制备了Dy³⁺或Tb³⁺单掺和Dy³⁺/Tb³⁺共掺硅酸盐氟氧闪烁玻璃。通过对傅里叶变换红外光谱、透射光谱、光致激发和发射光谱、X射线激发发射光谱及荧光衰减曲线的分析，研究Dy³⁺与Tb³⁺之间的能量传递关系以及Dy³⁺对Tb³⁺激活硅酸盐氟氧闪烁玻璃发光性能的影响。实验结果表明：Dy³⁺/Tb³⁺共掺硅酸盐氟氧闪烁玻璃具有较高的密度和良好的可见区透过率，玻璃的网络结构是由[SiO₄]四面体和[AlO₄]四面体连接构成。在紫外光激发时，Dy³⁺单掺玻璃的发光源于Dy³⁺的⁴F_9/2→⁶H_15/2(483 nm)，⁶H_13/2(576 nm)的跃迁发射，而Tb³⁺单掺玻璃的发光则源于Tb³⁺的⁵D₄→⁷F₆(489 nm)，⁷F₅(544 nm)，⁷F₄(586 nm)和⁷F₆(623 nm)的跃迁发射。对于Dy³⁺/Tb³⁺共掺玻璃，发射光谱则主要由Tb³⁺的荧光发射组成。通过对不同波长紫外光激发的发射光谱分析发现，Dy³⁺/Tb³⁺共掺闪烁玻璃中存在多种形式的能量传递。在以Dy³⁺的特征激发452 nm为激发波长时，Tb³⁺单掺玻璃的发光很弱。但随着Dy³⁺的引入，通过⁴F_9/2(Dy³⁺)→⁵D₄(Tb³⁺)的能量传递，Tb³⁺发光得到敏化增强。Dy³⁺/Tb³⁺共掺玻璃的发光强度随着Dy₂O₃含量的增多而增强，Dy₂O₃含量为1 mol%时达到最大，更高Dy₂O₃含量的样品由于Dy³⁺的浓度猝灭，减少了向Tb³⁺的能量传递，发光强度减弱。当激发波长减小到350 nm时，Dy³⁺和Tb³⁺均被激发到更高的能级⁶P_7/2(Dy³⁺)和⁵L₉(Tb³⁺)，此时除了⁴F_9/2(Dy³⁺)→⁵D₄(Tb³⁺)的能量传递外，还出现了⁵D₄(Tb³⁺)→⁴F_9/2(Dy³⁺)的能量回传。Dy³⁺掺杂浓度较低时，Dy³⁺→Tb³⁺能量传递作用较强，Tb³⁺发光得到敏化增强。随着Dy₂O₃含量的增多，Tb³⁺→Dy³⁺能量传递作用增强。当Dy₂O₃含量超过0.4 mol%时，Tb³⁺→Dy³⁺能量传递强于Dy³⁺→Tb³⁺能量传递，减少了Tb³⁺的辐射跃迁发光，因此Dy³⁺/Tb³⁺共掺玻璃的发光强度开始减弱。由于Gd³⁺向Dy³⁺或Tb³⁺均可进行有效的能量传递，因此在以Gd³⁺的特征激发274 nm为激发光时，Dy³⁺/Tb³⁺共掺玻璃中出现了Dy³⁺和Tb³⁺对Gd³⁺传递能量的竞争。随着Dy₂O₃含量的增多，Tb³⁺所获得的能量不断减少，同时伴随着Tb³⁺→Dy³⁺能量回传和Dy³⁺之间的无辐射交叉弛豫作用，Dy³⁺/Tb³⁺共掺玻璃的发光强度不断减弱。对Dy³⁺/Tb³⁺共掺闪烁玻璃中Tb³⁺的⁵D₄→⁷F₅荧光衰减曲线分析还发现，随着Dy₂O₃含量的增多，Tb³⁺的荧光寿命从2.24 ms缩短到1.15 ms，曲线从单指数形式变为双指数形式，进一步证明玻璃中存在⁵D₄(Tb³⁺)→⁴F_9/2(Dy³⁺)的能量回传。X射线激发发射光谱显示，Dy³⁺的引入对Tb³⁺激活闪烁玻璃的辐射发光具有很强的负面影响，而这种负面影响不足以通过Dy³⁺→Tb³⁺能量传递来弥补，因此Dy³⁺/Tb³⁺共掺玻璃的辐射发光强度随着Dy₂O₃含量的增多而不断减弱。由此可见，在Tb³⁺激活硅酸盐氟氧闪烁玻璃中，不宜将Dy³⁺作为敏化剂，用于增强Tb³⁺的发光。

关键词：闪烁玻璃；Dy³⁺/Tb³⁺共掺；X射线激发；能量传递

Abstract：Dy³⁺, Tb³⁺ doped and Dy³⁺/Tb³⁺ co-doped silicate oxyfluoride scintillating glass were prepared by high temperature melting method. The Fourier transform infrared spectra, transmission spectra, photoluminescence excitation and emission spectra, X-ray excited luminescence spectra and luminescence decay curves were analyzed. The influence of the energy transfer between Dy³⁺ and Tb³⁺ions and Dy³⁺doping onluminescence properties of Tb³⁺ activated silicate oxyfluoride scintillating glass was studied. The results indicated that Dy³⁺/Tb³⁺ co-doped silicate oxyfluoride scintillating glass has relatively high density and good transmittance in visible region. The networkstructure of glass isconstituted of tetrahedral [SiO₄] and [AlO₄]. Under the irradiation of ultraviolet light, the luminescence of Dy³⁺-doped glass originates from ⁴F_9/2→⁶H_15/2 (483 nm) and ⁶H_13/2 (576 nm) transition emission of Dy³⁺ ions, while the luminescence of Tb³⁺-doped glass originates from ⁵D₄→⁷F₆ (489 nm), ⁷F₅ (544 nm), ⁷F₄ (586 nm) and ⁷F₆ (623 nm) transition emission of Tb³⁺ ions. As for Dy³⁺/Tb³⁺ co-doped silicate oxyfluoride scintillating glasses, the emission spectra aremainly due to fluorescence emission of Tb³⁺ ions. The emission spectra under ultraviolet excitation with different wavelengths revealed that Dy³⁺/Tb³⁺ co-doped scintillating glass includes manifold energy transfers. When Tb³⁺-doped glass is excited by the characteristic excitation wavelength (452 nm) of Dy³⁺ ions, the luminous intensity of Tb³⁺-doped glass is very weak. With the introduction of Dy³⁺ ions, Tb³⁺ ions emission are sensitized and enhanced by the energy transfer of ⁴F_9/2 (Dy³⁺)→⁵D₄ (Tb³⁺). The luminous intensity ofDy³⁺/Tb³⁺ co-doped glassesis improved with the increase of Dy₂O₃. The luminous intensity ofDy³⁺/Tb³⁺ co-doped glasses reaches the maximum when the content of Dy₂O₃ is 1mol%. However, when the content of Dy₂O₃ is further increased, the concentration of Dy³⁺ ions is quenched, which results in the decrease of the energy transfer to Tb³⁺ions and the reduction of the luminous intensity. When the excitation wavelength is decreased to 350 nm, Dy³⁺ and Tb³⁺ ions are excited to higher energy levels of ⁶P_7/2 (Dy³⁺) and ⁵L₉ (Tb³⁺). At this point, the energy transfer of both ⁴F_9/2 (Dy³⁺)→⁵D₄ (Tb³⁺) and ⁵D₄(Tb³⁺)→⁴F_9/2 (Dy³⁺) occurs. When the doping concentration of Dy³⁺ ions is relatively low, the energy transfer of Dy³⁺→Tb³⁺ is stronger than that of Tb³⁺→Dy³⁺, which enhancesthe luminescence of Tb³⁺ ions by sensitization. With the increase of Dy₂O₃ content, the energy transfer of Tb³⁺→Dy³⁺ is enhanced. When the content of Dy₂O₃ is above 0.4 mol%, the energy transfer of Tb³⁺→Dy³⁺ is strongerthan that of Dy³⁺→Tb³⁺, which reduces the transition luminescence of Tb³⁺ ions and thus decreases theluminous intensity of Dy³⁺/Tb³⁺ co-doped glass. Due to the efficient energy transfer from Gd³⁺ to Dy³⁺ or Tb³⁺, the competition of energy transferfrom Gd³⁺ to Dy³⁺ and Tb³⁺ion soccurs under characteristic excitation wavelength of Gd³⁺ ion at 274 nm. With the increase of content of Dy₂O₃, the captured energy of Tb³⁺ions decreases constantly. At the same time, the energy backtransfer of Tb³⁺→Dy³⁺ and the nonradiative cross relaxation between Dy³⁺ ions appear, which leads to the reduction of theluminous intensity of Dy³⁺/Tb³⁺ co-doped glass. The ⁵D₄→⁷F₅ luminescence decay curves of Tb³⁺ions for Dy³⁺/Tb³⁺co-doped scintillating glass showed that with the increase of Dy₂O₃ content, the lifetime of ⁵D₄ (Tb³⁺) reduces from 2.24 to 1.15 ms and the curve changes from single-exponential to double-exponential form, indicating the possibility of the energy back transfer of ⁵D₄ (Tb³⁺)→⁴F_9/2 (Dy³⁺) in the glass. The X-ray excited luminescence emission spectra showed that the introduction of Dy³⁺ ions has a negative effect on the luminescence of Tb³⁺ activated scintillating glass. Becausethat negative effect is not enough to make up for the Dy³⁺→Tb³⁺ energy transfer, the radiation luminescence intensity of Dy³⁺/Tb³⁺ co-doped glass decreases with the increase of the Dy₂O₃ content. Therefore, Dy³⁺ ions should not be used as sensitizers to enhance the luminescence intensity of Tb³⁺ ions in Tb³⁺ activated silicate oxyfluoride scintillating glass.

Key words：Scintillating glass；Dy³⁺/Tb³⁺ co-doped；X-ray excitation；Energy transfer

收稿日期: 2018-02-01 修订日期: 2018-06-22

中图分类号:

O482.31

基金资助: 国家重点研发计划项目（2017YFF0108607），国家自然科学基金项目（61775081），吉林省教育厅“十三五”科学技术研究规划项目(JJKHZ20180783KJ)，吉林师范大学博士科研启动项目（吉师博2017001号）资助

通讯作者: 杨丽丽 E-mail: llyang1980@126.com

作者简介: 张勇，1982年生，吉林师范大学物理学院副教授 e-mail: zhangyong@jlnu.edu.cn

引用本文:

张勇，朱金铭，杨丽丽，吕世权，武彦群，楚学娟. Dy³⁺对Tb³⁺激活硅酸盐氟氧闪烁玻璃发光性能的影响[J]. 光谱学与光谱分析, 2019, 39(05): 1412-1419.
ZHANG Yong, ZHU Jin-ming, YANG Li-li, Lü Shi-quan, WU Yan-qun，CHU Xue-juan. Effect of Dy³⁺ on Luminescence Properties of Tb³⁺ Activated Silicate Oxyfluoride Scintillating Glass. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2019, 39(05): 1412-1419.

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https://www.gpxygpfx.com/CN/10.3964/j.issn.1000-0593(2019)05-1412-08 或 https://www.gpxygpfx.com/CN/Y2019/V39/I05/1412