Dy~(3+)对Tb~(3+)激活硅酸盐氟氧闪烁玻璃发光性能的影响
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摘要
采用高温熔融法制备了Dy~(3+)或Tb~(3+)单掺和Dy~(3+)/Tb~(3+)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Dy~(3+)与Tb~(3+)之间的能量传递关系以及Dy~(3+)对Tb~(3+)激活硅酸盐氟氧闪烁玻璃发光性能的影响。实验结果表明:Dy~(3+)/Tb~(3+)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[SiO_4]四面体和[AlO_4]四面体连接构成。在紫外光激发时, Dy~(3+)单掺玻璃的发光源于Dy~(3+)的~4F_(9/2)→~6H_(15/2)(483 nm),~6H_(13/2)(576 nm)的跃迁发射,而Tb~(3+)单掺玻璃的发光则源于Tb~(3+)的~5D_4→~7F_6(489 nm),~7F_5(544 nm),~7F_4(586 nm)和~7F_6(623 nm)的跃迁发射。对于Dy~(3+)/Tb~(3+)共掺玻璃,发射光谱则主要由Tb~(3+)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, Dy~(3+)/Tb~(3+)共掺闪烁玻璃中存在多种形式的能量传递。在以Dy~(3+)的特征激发452 nm为激发波长时, Tb~(3+)单掺玻璃的发光很弱。但随着Dy~(3+)的引入,通过~4F_(9/2)(Dy~(3+))→~5D_4(Tb~(3+))的能量传递, Tb~(3+)发光得到敏化增强。Dy~(3+)/Tb~(3+)共掺玻璃的发光强度随着Dy_2O_3含量的增多而增强, Dy_2O_3含量为1 mol%时达到最大,更高Dy_2O_3含量的样品由于Dy~(3+)的浓度猝灭,减少了向Tb~(3+)的能量传递,发光强度减弱。当激发波长减小到350 nm时, Dy~(3+)和Tb~(3+)均被激发到更高的能级~6P_(7/2)(Dy~(3+))和~5L_9(Tb~(3+)),此时除了~4F_(9/2)(Dy~(3+))→~5D_4(Tb~(3+))的能量传递外,还出现了~5D_4(Tb~(3+))→~4F_(9/2)(Dy~(3+))的能量回传。Dy~(3+)掺杂浓度较低时, Dy~(3+)→Tb~(3+)能量传递作用较强, Tb~(3+)发光得到敏化增强。随着Dy_2O_3含量的增多, Tb~(3+)→Dy~(3+)能量传递作用增强。当Dy_2O_3含量超过0.4 mol%时, Tb~(3+)→Dy~(3+)能量传递强于Dy~(3+)→Tb~(3+)能量传递,减少了Tb~(3+)的辐射跃迁发光,因此Dy~(3+)/Tb~(3+)共掺玻璃的发光强度开始减弱。由于Gd~(3+)向Dy~(3+)或Tb~(3+)均可进行有效的能量传递,因此在以Gd~(3+)的特征激发274 nm为激发光时, Dy~(3+)/Tb~(3+)共掺玻璃中出现了Dy~(3+)和Tb~(3+)对Gd~(3+)传递能量的竞争。随着Dy_2O_3含量的增多, Tb~(3+)所获得的能量不断减少,同时伴随着Tb~(3+)→Dy~(3+)能量回传和Dy~(3+)之间的无辐射交叉弛豫作用, Dy~(3+)/Tb~(3+)共掺玻璃的发光强度不断减弱。对Dy~(3+)/Tb~(3+)共掺闪烁玻璃中Tb~(3+)的~5D_4→~7F_5荧光衰减曲线分析还发现,随着Dy_2O_3含量的增多, Tb~(3+)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~5D_4(Tb~(3+))→~4F_(9/2)(Dy~(3+))的能量回传。X射线激发发射光谱显示, Dy~(3+)的引入对Tb~(3+)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Dy~(3+)→Tb~(3+)能量传递来弥补,因此Dy~(3+)/Tb~(3+)共掺玻璃的辐射发光强度随着Dy_2O_3含量的增多而不断减弱。由此可见,在Tb~(3+)激活硅酸盐氟氧闪烁玻璃中,不宜将Dy~(3+)作为敏化剂,用于增强Tb~(3+)的发光。
Dy~(3+), Tb~(3+) doped and Dy~(3+)/Tb~(3+) 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 Dy~(3+) and Tb~(3+)ions and Dy~(3+)doping onluminescence properties of Tb~(3+) activated silicate oxyfluoride scintillating glass was studied. The results indicated that Dy~(3+)/Tb~(3+) co-doped silicate oxyfluoride scintillating glass has relatively high density and good transmittance in visible region. The networkstructure of glass isconstituted of tetrahedral [SiO_4] and [AlO_4]. Under the irradiation of ultraviolet light, the luminescence of Dy~(3+)-doped glass originates from ~4F_(9/2)→~6H_(15/2)(483 nm) and ~6H_(13/2)(576 nm) transition emission of Dy~(3+) ions, while the luminescence of Tb~(3+)-doped glass originates from ~5D_4→~7F_6(489 nm), ~7F_5(544 nm), ~7F_4(586 nm) and ~7F_6(623 nm) transition emission of Tb~(3+) ions. As for Dy~(3+)/Tb~(3+) co-doped silicate oxyfluoride scintillating glasses, the emission spectra aremainly due to fluorescence emission of Tb~(3+) ions. The emission spectra under ultraviolet excitation with different wavelengths revealed that Dy~(3+)/Tb~(3+) co-doped scintillating glass includes manifold energy transfers. When Tb~(3+)-doped glass is excited by the characteristic excitation wavelength(452 nm) of Dy~(3+) ions, the luminous intensity of Tb~(3+)-doped glass is very weak. With the introduction of Dy~(3+) ions, Tb~(3+) ions emission are sensitized and enhanced by the energy transfer of ~4F_(9/2)(Dy~(3+))→~5D_4(Tb~(3+)). The luminous intensity ofDy~(3+)/Tb~(3+) co-doped glassesis improved with the increase of Dy_2O_3. The luminous intensity ofDy~(3+)/Tb~(3+) co-doped glasses reaches the maximum when the content of Dy_2O_3 is 1 mol%. However, when the content of Dy_2O_3 is further increased, the concentration of Dy~(3+) ions is quenched, which results in the decrease of the energy transfer to Tb~(3+)ions and the reduction of the luminous intensity. When the excitation wavelength is decreased to 350 nm, Dy~(3+) and Tb~(3+) ions are excited to higher energy levels of ~6P_(7/2)(Dy~(3+)) and ~5L_9(Tb~(3+)). At this point, the energy transfer of both ~4F_(9/2)(Dy~(3+))→~5D_4(Tb~(3+)) and ~5D_4(Tb~(3+))→~4F_(9/2)(Dy~(3+)) occurs. When the doping concentration of Dy~(3+) ions is relatively low, the energy transfer of Dy~(3+)→Tb~(3+) is stronger than that of Tb~(3+)→Dy~(3+), which enhancesthe luminescence of Tb~(3+) ions by sensitization. With the increase of Dy_2O_3 content, the energy transfer of Tb~(3+)→Dy~(3+) is enhanced. When the content of Dy_2O_3 is above 0.4 mol%, the energy transfer of Tb~(3+)→Dy~(3+) is strongerthan that of Dy~(3+)→Tb~(3+), which reduces the transition luminescence of Tb~(3+) ions and thus decreases theluminous intensity of Dy~(3+)/Tb~(3+) co-doped glass. Due to the efficient energy transfer from Gd~(3+) to Dy~(3+) or Tb~(3+), the competition of energy transferfrom Gd~(3+) to Dy~(3+) and Tb~(3+)ion soccurs under characteristic excitation wavelength of Gd~(3+) ion at 274 nm. With the increase of content of Dy_2O_3, the captured energy of Tb~(3+)ions decreases constantly. At the same time, the energy backtransfer of Tb~(3+)→Dy~(3+) and the nonradiative cross relaxation between Dy~(3+) ions appear, which leads to the reduction of theluminous intensity of Dy~(3+)/Tb~(3+) co-doped glass. The ~5D_4→~7F_5 luminescence decay curves of Tb~(3+)ions for Dy~(3+)/Tb~(3+)co-doped scintillating glass showed that with the increase of Dy_2O_3 content, the lifetime of ~5D_4(Tb~(3+)) 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 ~5D_4(Tb~(3+))→~4F_(9/2)(Dy~(3+)) in the glass. The X-ray excited luminescence emission spectra showed that the introduction of Dy~(3+) ions has a negative effect on the luminescence of Tb~(3+) activated scintillating glass. Becausethat negative effect is not enough to make up for the Dy~(3+)→Tb~(3+) energy transfer, the radiation luminescence intensity of Dy~(3+)/Tb~(3+) co-doped glass decreases with the increase of the Dy_2O_3 content. Therefore, Dy~(3+) ions should not be used as sensitizers to enhance the luminescence intensity of Tb~(3+) ions in Tb~(3+) activated silicate oxyfluoride scintillating glass.
Dy~(3+), Tb~(3+) doped and Dy~(3+)/Tb~(3+) 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 Dy~(3+) and Tb~(3+)ions and Dy~(3+)doping onluminescence properties of Tb~(3+) activated silicate oxyfluoride scintillating glass was studied. The results indicated that Dy~(3+)/Tb~(3+) co-doped silicate oxyfluoride scintillating glass has relatively high density and good transmittance in visible region. The networkstructure of glass isconstituted of tetrahedral [SiO_4] and [AlO_4]. Under the irradiation of ultraviolet light, the luminescence of Dy~(3+)-doped glass originates from ~4F_(9/2)→~6H_(15/2)(483 nm) and ~6H_(13/2)(576 nm) transition emission of Dy~(3+) ions, while the luminescence of Tb~(3+)-doped glass originates from ~5D_4→~7F_6(489 nm), ~7F_5(544 nm), ~7F_4(586 nm) and ~7F_6(623 nm) transition emission of Tb~(3+) ions. As for Dy~(3+)/Tb~(3+) co-doped silicate oxyfluoride scintillating glasses, the emission spectra aremainly due to fluorescence emission of Tb~(3+) ions. The emission spectra under ultraviolet excitation with different wavelengths revealed that Dy~(3+)/Tb~(3+) co-doped scintillating glass includes manifold energy transfers. When Tb~(3+)-doped glass is excited by the characteristic excitation wavelength(452 nm) of Dy~(3+) ions, the luminous intensity of Tb~(3+)-doped glass is very weak. With the introduction of Dy~(3+) ions, Tb~(3+) ions emission are sensitized and enhanced by the energy transfer of ~4F_(9/2)(Dy~(3+))→~5D_4(Tb~(3+)). The luminous intensity ofDy~(3+)/Tb~(3+) co-doped glassesis improved with the increase of Dy_2O_3. The luminous intensity ofDy~(3+)/Tb~(3+) co-doped glasses reaches the maximum when the content of Dy_2O_3 is 1 mol%. However, when the content of Dy_2O_3 is further increased, the concentration of Dy~(3+) ions is quenched, which results in the decrease of the energy transfer to Tb~(3+)ions and the reduction of the luminous intensity. When the excitation wavelength is decreased to 350 nm, Dy~(3+) and Tb~(3+) ions are excited to higher energy levels of ~6P_(7/2)(Dy~(3+)) and ~5L_9(Tb~(3+)). At this point, the energy transfer of both ~4F_(9/2)(Dy~(3+))→~5D_4(Tb~(3+)) and ~5D_4(Tb~(3+))→~4F_(9/2)(Dy~(3+)) occurs. When the doping concentration of Dy~(3+) ions is relatively low, the energy transfer of Dy~(3+)→Tb~(3+) is stronger than that of Tb~(3+)→Dy~(3+), which enhancesthe luminescence of Tb~(3+) ions by sensitization. With the increase of Dy_2O_3 content, the energy transfer of Tb~(3+)→Dy~(3+) is enhanced. When the content of Dy_2O_3 is above 0.4 mol%, the energy transfer of Tb~(3+)→Dy~(3+) is strongerthan that of Dy~(3+)→Tb~(3+), which reduces the transition luminescence of Tb~(3+) ions and thus decreases theluminous intensity of Dy~(3+)/Tb~(3+) co-doped glass. Due to the efficient energy transfer from Gd~(3+) to Dy~(3+) or Tb~(3+), the competition of energy transferfrom Gd~(3+) to Dy~(3+) and Tb~(3+)ion soccurs under characteristic excitation wavelength of Gd~(3+) ion at 274 nm. With the increase of content of Dy_2O_3, the captured energy of Tb~(3+)ions decreases constantly. At the same time, the energy backtransfer of Tb~(3+)→Dy~(3+) and the nonradiative cross relaxation between Dy~(3+) ions appear, which leads to the reduction of theluminous intensity of Dy~(3+)/Tb~(3+) co-doped glass. The ~5D_4→~7F_5 luminescence decay curves of Tb~(3+)ions for Dy~(3+)/Tb~(3+)co-doped scintillating glass showed that with the increase of Dy_2O_3 content, the lifetime of ~5D_4(Tb~(3+)) 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 ~5D_4(Tb~(3+))→~4F_(9/2)(Dy~(3+)) in the glass. The X-ray excited luminescence emission spectra showed that the introduction of Dy~(3+) ions has a negative effect on the luminescence of Tb~(3+) activated scintillating glass. Becausethat negative effect is not enough to make up for the Dy~(3+)→Tb~(3+) energy transfer, the radiation luminescence intensity of Dy~(3+)/Tb~(3+) co-doped glass decreases with the increase of the Dy_2O_3 content. Therefore, Dy~(3+) ions should not be used as sensitizers to enhance the luminescence intensity of Tb~(3+) ions in Tb~(3+) activated silicate oxyfluoride scintillating glass.
引文
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[2] Liu Liwan,Shao Chongyun,Zhang Yu,et al.Journal of Luminescence,2016,176:1.
[3] Chewpraditkul W,Shen Y L,Chen D P,et al.Optical Materials,2013,35(3):426.
[4] Duan Jiao,Liu Yan,Pan Xiuhong,et al.Materials Letters,2016,173:102.
[5] Jia Shijie,Huang Lihui,Ma Donglei,et al.Journal of Luminescence,2014,152(1):241.
[6] Zhang Yong,Lv Jingwen,Ding Ning,et al.Journal of Non-Crystalline Solids,2015,423-424:30.
[7] Zhang Yong,Ding Ning,Zheng Tao,et al.Journal of Non-Crystalline Solids,2016,441:74.
[8] Lakshminarayana G,Kaky Kawa M,Baki S O,et al.Optical Materials,2017,72:380.
[9] Lesniak M,Partyka J,Pasiut K,et al.Journal of Molecular Structure,2016,1126:240.
[10] Wang Mitang,Fang Long,Li Mei,et al,Materials Chemistry and Physics,2016,179:304.
[11] Sun Xinyuan,Yu Xiaoguang,Jiang Daguo,et al.Journal of Applied Physics,2016,119(23):233103.
[12] Caldiňo U,Muňoz H G,Camarillo I,et al.Journal of Luminescence,2015,161:142.
[13] WANG Qian,ZHANG Wei-huan,OUYANG Shao-ye,et al(王倩,张为欢,欧阳绍业,等).Acta Photonica Sinica(光子学报),2015,44(1):168.
[14] Sillen A,Engelborghs Y.Photochemistry and Photobiology,1998,67(5):475.
[15] Martin Nikl.Measurement Science and Technology,2006,17(4):R37.