SrAl_2O_4:Eu^(2+)和SrAl_2O_4:Eu^(2+),Dy^(3+)长余辉和热释光谱

Afterglow and thermoluminescence spectra of SrAl_2O_4:Eu^(2+) and SrAl_2O_4:Eu^(2+),Dy^(3+)

采用高温固相法在弱还原气氛中,1300°C合成了掺杂Eu^(2+)和Dy^(3+)离子的SrAl_2O_4。对比研究了SrAl_2O_4:Eu^(2+)和SrAl_2O_4:Eu^(2+),Dy^(3+)的余辉特性和热释光谱,并探讨了Dy^(3+)的掺杂对SrAl_2O_4:Eu^(2+)陷阱能级的影响。XRD分析表明:Eu^(2+)和Dy^(3+)的掺杂没有改变SrAl_2O_4的晶相。光致发光分析表明:Dy^(3+)的掺杂没有改变SrAl_2O_4:Eu^(2+)的光致发光光谱和发光中心。热释光谱对比分析结果显示:Eu^(2+)的掺杂在SrAl_2O_4的禁带中引入了两个深度不同的陷阱能级;Dy^(3+)的掺杂不改变原来陷阱能级的深度,却能够显著地增加原来浅陷阱能级的密度,从而改善SrAl_2O_4:Eu^(2+)的余辉特性。不同等待时间的热释光谱曲线显示;在室温下,不同陷阱能级衰减规律的差异以及陷阱能级间存在的电子转移,可能造成了SrAl_2O_4:Eu^(2+),Dy^(3+)长余辉材料复杂的余辉衰减规律。

Phosphors SrAl2O4 doped by Eu^2＋ and Dy^3＋ ions were synthesized by a solid-state reaction at 1300℃ under mild reducing atmosphere of N2-H2. The properties of afterglow and thermoluminescence spectra of SrAl2O4：Eu^2＋and SrAl2O4：Eu^2＋, Dy^3＋ were compared and the influence on trap levels of SrAl2O4：Eu^2＋ by codoping Dy^3＋ was also studied. From the XRD and photoluminescence results, the crystal phase and luminescence band are not changed by codoping Dy^3＋. The thermoluminescence spectra show that the dopant of Eu^2＋ ions could lead into two trap levels with different depth in SrAl2O4. The result of comparison of thermoluminescence properties of SrAl2O4：Eu^2＋ and SrAl2O4：Eu^2＋, Dy^3＋ after different delay time indicates that the density of the original shallow traps is increased by the codopant of Dy^3＋, and the luminescence performance is improved. The thermoluminescence with different delay time indicates that the luminescence decay difference and electron transfer between trap levels in SrAl2O4：Eu^2＋, Dy^3＋ may result in the complicated decay phenomena of the afterglow.