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

摘要: 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。

Abstract: 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⁺.