Abstract We examined the optical properties of sintered layered double hydroxides (LDH) as phosphors. Eu3+-doped Mg Al LDH and Ca Al LDH were synthesized via co-precipitation methods. We sintered the obtained LDH at temperatures ranging from 300 to 1000 °C. The sintered Mg Al LDH showed the same X-ray diffraction (XRD) pattern as rock salt in the temperature range between 300 and 800 °C and partly transitioned to spinel at 1000 °C. The sintered LDH showed red luminescence with a main peak at 613 nm. This dominant red luminescence is assigned to the 5D0-7F2 electric dipole transition of Eu3+, which is allowed for structures without inversion symmetry. The dominant intensity of the electric dipole transition is inconsistent with the highly symmetric rock salt structure. We concluded that this phenomenon is triggered by the reduction of symmetry around the Eu3+ ion due to the introduction of the Al3+ ion and the cation vacancy in the MgO rock salt host and/or the strain induced by the introduction of these dopants. Our conclusion is based on the X-ray absorption near edge structure (XANES) data and the extended X-ray absorption fine structure (EXAFS) analysis of the sintered Ni Ti LDH with the same rock salt structure as the sintered Mg Al LDH. Eu2+-doped Mg Al and Ca Al binary metal oxides, synthesized by sintering Eu3+-doped Mg Al and Ca Al LDH in quartz tubes in the presence of Ti powder, showed broad peaks at the green (540 nm) and blue (440 nm) light regions, respectively. These results have demonstrated that red-green-blue (RGB) luminescence can be obtained using a uni-type host structure.

中文翻译：

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由烧结层状双氢氧化物获得的铕 (II) 和 (III) 离子掺杂金属氧化物的光学性质及其精细结构

摘要 我们研究了烧结层状双氢氧化物 (LDH) 作为荧光粉的光学特性。Eu3+掺杂的Mg Al LDH和Ca Al LDH是通过共沉淀法合成的。我们在 300 到 1000 °C 的温度下烧结获得的 LDH。烧结的 Mg Al LDH 在 300 至 800 °C 的温度范围内显示出与岩盐相同的 X 射线衍射 (XRD) 图案，并在 1000 °C 时部分转变为尖晶石。烧结后的 LDH 显示红色发光，主峰位于 613 nm。这种主要的红色发光归因于 Eu3+ 的 5D0-7F2 电偶极跃迁，这对于没有反转对称性的结构是允许的。电偶极子跃迁的主导强度与高度对称的岩盐结构不一致。我们得出的结论是，这种现象是由于引入 Al3+ 离子和 MgO 岩盐基质中的阳离子空位和/或引入这些掺杂剂引起的应变导致 Eu3+ 离子周围对称性降低而触发的。我们的结论是基于 X 射线吸收近边结构 (XANES) 数据和具有与烧结 Mg Al LDH 相同岩盐结构的烧结 Ni Ti LDH 的扩展 X 射线吸收精细结构 (EXAFS) 分析。Eu2+ 掺杂的 Mg Al 和 Ca Al 二元金属氧化物，通过在石英管中在 Ti 粉末存在下烧结 Eu3+ 掺杂的 Mg Al 和 Ca Al LDH 合成，在绿色 (540 nm) 和蓝色 (440 nm) 处显示出宽峰分别为浅色区域。这些结果表明，使用单型主体结构可以获得红-绿-蓝 (RGB) 发光。