基于Eu³⁺-Sm³⁺掺杂CaWO₄基质的发光特性及能量传递机理研究

Photoluminescence and Energy Transfer Properties of Eu³⁺-Sm³⁺ Co-Doped CaWO₄ Phosphors

通过高温固相法制备系列Eu3+,Sm3+单掺杂和Eu3+-Sm3+共掺杂CaWO4荧光粉。X射线粉末衍射(XRD)法测试发现,Eu3+,Sm3+单掺杂和Eu3+-Sm3+共掺杂没有影响目标样品晶相。样品的荧光光谱表明,掺杂离子Eu3+和Sm3+可以被基质的激发波长激发,Eu3+的发射可被Sm3+的特征激发峰激发,且Eu3+的最佳掺杂浓度为0.10。除此之外,Eu3+-Sm3+共掺杂样品的光谱表明,在Eu3+浓度固定不变时,在Sm3+的激发波长激发下,随Sm3+浓度的增加,Sm3+的发射强度会出现先增后减,而Eu3+的发射强度仅会随Sm3+浓度的增加而增强。由此证明,Eu3+和Sm3+在CaWO4基质中,Eu3+和Sm3+掺杂离子以及掺杂离子Sm3+和Eu3+之间具有能量传递。

In this work, a series of Eu3+, Sm3+ singly doped and Eu3+-Sm3+ co-doped CaWO4 phosphors were successfully synthesized via the conventional high temperature state reaction. The XRD results showed that doping Eu3+ and Sm3+ into CaWO4 host did not change the scheelite crystal structure of our samples. The photoluminescence spectra revealed that upon excitation at the excitation wavelength of host (e.g., 247 nm) could give rise to pumping the Eu3+ and Sm3+ emissions, and, in the meanwhile, using the characteristic excitation wavelength of Sm3+ (e.g., 404 nm) could also induce the Eu3+ emission. In addition, we experimentally found that the optimal Eu3+ doping con-tent which corresponds to the maximum Eu3+ emission intensity was 0.10. Furthermore, the pho-toluminescence results found that increasing the Sm3+ doping content in the Eu3+-Sm3+ co-doped CaWO4 phosphors could induce an Sm3+ initial emission intensity and then a subsequent decrease but constantly increased the Eu3+ emission intensity. The results we presented here had illustrated that there exists the energy transfer from the CaWO4 host to the Eu3+ and Sm3+ dopants and from the dopant of Sm3+ to the dopant of Eu3+.