Crystal Structures, Phase-Transition, and Photoluminescence of Rare Earth Carbodiimides
Crystal Structures, Phase-Transition, and Photoluminescence of Rare Earth Carbodiimides
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DOI：
10.1021/ic800985k
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发表时间：
2008-11-17
影响因子：
4.6
通讯作者：
Meyer, H. -Juergen
中科院分区：
文献类型：
--
作者：
Glaser, Jochen;Unverfehrt, Leonid;Meyer, H. -Juergen
具有通式RE 2（CN 2）（3）的稀土双酰亚胺以两种变体结晶。RE = Y，Ce-Tm为单斜晶系（C ~ 2/m），RE = Tm-Lu为菱面晶系（R（3）over barc）。Lu-2（CN ~ 2）（3）的单晶结构测定和RE = Tm，Yb，Lu的粉末衍射图证实了空间群R（3）over barc。Tm-2（CN 2）（3）的不同化学合成条件的使用揭示了该化合物的二晶型特征。此外，对Tm-2（CN 2）（3）的压力实验已经诱导了从菱面体到单斜的相变。这种转变包括Tm的配位数从6增加到7，以及晶胞体积减少约20%。研究了稀土掺杂Gd-2（CN 2）（3）：Ln样品在不同激活剂（Ln = Ce，Tb）作用下的光致发光行为，发现Gd-2（CN 2）（3）：Ce具有与YAG：Ce类似的宽带发光。
Rare earth carbodiimides with the general formula RE2(CN2)(3) crystallize with two modifications. A monoclinic (C2/m) modification is obtained for RE = Y, Ce-Tm and a rhombohedral (R (3) over barc) modification for RE = Tm-Lu, The space group R (3) over barc is confirmed by single-crystal structure determination on Lu-2(CN2)(3) and indexed powder patterns of RE = Tm, Yb and Lu. The use of diverse chemical syntheses conditions for Tm-2(CN2)(3) revealed the dimorphic character of this compound. In addition, pressure experiments on Tm-2(CN2)(3) have induced a phase-transition from rhombohedral to monoclinic. This transformation comprises an increase of the coordination number of Tm from 6 to 7, and a unit-cell volume reduction in the order of 20 %. The photoluminescence behavior of lanthanide doped Gd-2(CN2)(3):Ln samples is presented with different activators (Ln = Ce, Tb) revealing a broad band emission of Gd-2(CN2)(3):Ce, quite similar to that of the well-known YAG:Ce.