School of Materials Sciences and Technology, China University of Geosciences, Beijing 100083, China.
Dalton Trans. 2013 Dec 21;42(47):16588-95. doi: 10.1039/c3dt52232f.
The substituted activator ions Eu(2+) in the β-Ca3(PO4)2-type structure, Ca9NaMg(PO4)7 compound, have been studied as emission centers, as well as structural probes. The crystal structure and crystallographic sites of Eu(2+) in Ca9NaMg(PO4)7 have been identified by Rietveld refinements, electron paramagnetic resonance (EPR) spectroscopy analysis and combined photoluminescence spectral analysis, respectively. Ca9NaMg(PO4)7:Eu(2+) phosphor exhibits a broad emission band in the visible light region with three distinguished peaks centered at 415, 458, and 615 nm, which are ascribed to different Eu(2+) emission centers occupied in three different Ca crystallographic sites. The concentration quenching behavior, variation in lifetimes and the temperature dependent luminescence properties have been investigated as a function of different emission centers, 415, 458, and 625 nm for Ca9NaMg(PO4)7:Eu(2+) phosphor. Accordingly, the relationship among three different Eu(2+) luminescence centers originating from three different Ca(2+) crystallographic sites has been found and verified.
Eu(2+) 取代了 β-Ca3(PO4)2 型结构中的激活剂离子 Ca9NaMg(PO4)7 化合物，它被用作发射中心和结构探针。通过 Rietveld 精修、电子顺磁共振（EPR）光谱分析和组合荧光光谱分析，分别确定了 Ca9NaMg(PO4)7 中 Eu(2+)的晶体结构和晶体位置。Ca9NaMg(PO4)7:Eu(2+) 荧光粉在可见光区域显示出一个宽的发射带，有三个明显的峰值，中心分别位于 415nm、458nm 和 615nm，归因于三个不同的 Ca 晶体位置上占据的不同 Eu(2+)发射中心。研究了 Ca9NaMg(PO4)7:Eu(2+)荧光粉作为不同发射中心时的浓度猝灭行为、寿命变化和温度依赖的发光性能，415nm、458nm 和 625nm。因此，发现并验证了三个不同 Ca(2+)晶体位置上的三个不同 Eu(2+)发光中心之间的关系。
