Mixed Anionic Metal Hydrides as Host Lattices for the Luminescence of Divalent Europium

无机主体晶格中的二价铕（Eu(II)）在照明器件中的应用备受关注。在氧化物基化合物和卤化物中，在紫外光（光致发光）激发下，它通常显示蓝色或绿色发射。有了更多的极化配体，如氮化物或氢化物，发射就会变成黄色、橙色或红色。通过对混合阴离子氢化物主体材料的研究，我们希望系统地研究掺杂剂浓度、键长、氢化物配体数目、软硬阴离子混合、配位数和对称性对发光性能的影响。这些材料将掺杂不同量的铕（0.1-2%），并通过x射线衍射，中子衍射和发光光谱进行表征，包括极高分辨率光谱，低温和寿命测量。氢化物主体材料将主要来自各种类型的离子混合阴离子金属氢化物，如钙钛矿型氢化物KCaH3-xFx (1 < x < 3)，焦氯化物型氢化物和氢化物氧化物NaCaMg2F7-xHx， NaSrMg2F7-xHx， KCaNb2O6F1-xHx和KCaTa2O6F1-xHx，卤化物氢化物MHX (M = Ca, Sr, Ba; x = Cl, Br， I)，镧系氢化物氧化物LnHO和氢化物硅酸盐。识别和量化这些化合物中Eu（II）发光的晶体化学关键参数，将使我们能够预测所选发射波长下铕原子周围的理想化学环境，提出合适的晶体结构，从而实现发光材料的知识驱动开发。这将在一定程度上加深对混合阴离子金属氢化物中Eu（II）发光的理解，为寻找新的发光材料提供指导。

Divalent europium, Eu(II), in inorganic host lattices is of great interest for applications in lighting devices. In oxide based compounds and in halogenides, it usually shows blue or green emission upon excitation with UV light (photoluminescence). With more polarizable ligands, such as nitrides or hydrides, the emission shifts to yellow, orange or red. By investigating mixed anionic hydridic host materials, we want to systematize the influence of dopant concentration, bond length, number of hydride ligands, mixing of hard and soft anions, coordination number and symmetry on luminescence properties. These materials will be doped with different amounts of europium (0.1-2%) and characterized by X-ray diffraction, neutron diffraction and luminescence spectroscopy, including very high resolution spectra, low temperature and measurements of lifetime. Hydridic host materials will be from various classes of mainly ionic mixed anionic metal hydrides, e. g. perovskite-type hydride fluorides KCaH3-xFx (1 < x < 3), pyrochlore-type hydride fluorides and hydride oxides NaCaMg2F7-xHx, NaSrMg2F7-xHx, KCaNb2O6F1-xHx, and KCaTa2O6F1-xHx, hydride halogenides MHX (M = Ca, Sr, Ba; X = Cl, Br, I), lanthanide hydride oxides LnHO, and hydride silicates. Identifying and quantifying the crystal chemical key parameters for Eu(II) luminescence in such compounds will enable us to make predictions for the ideal chemical environment around europium atoms for a chosen emission wavelength, to suggest suitable crystal structures and thus the knowledge-driven development of luminescence materials. This will provide a deep understanding of Eu(II) luminescence in mixed-anionic metal hydrides at a level, where it can be used as a guide for the search of new luminescence materials.