Abstract The development of functional materials with synergistic properties, including fluorescent probes based on a metal-organic framework (MOFs) and lanthanide ions with dual emission, has attracted interest from the scientific community. In this regard, a series of ZIF-8 materials containing europium ions (ZIF-8:x% Eu where, x = 1, 3 or 7%) was prepared by a simple and fast method at room temperature (25 °C) and the structural, morphological and photophysical properties were evaluated. The results showed that the insertion of europium ions decreases the degree of crystallinity from 71% for ZIF-8 to 67%, 54% and 32% for ZIF-8:1% Eu, ZIF-8:3% Eu and ZIF-8:7% Eu, respectively. Nevertheless, the crystalline structure of ZIF-8 is maintained and only a small displacement in the planes was observed, which can be attributed to the substitution of europium ions in the zinc sites of the MOF structure. In general, the presence of europium ions improved the thermal stability and decreased the surface area compared to undoped ZIF-8. The emission spectra for the Eu-doped ZIF-8 reveal a signal in the blue region related to ZIF-8 emission and line profiles of the Eu3+ ion in the coordination polymer, which are in accordance with the formation of a heterostructured material with dual emission. In addition, the europium f-f transitions increased in intensity with the amount Eu3+, indicating an increment in the efficiency of this energy transfer. This study provides an example of progress in developing dual-emission MOFs based on the synergy properties of ZIF-8 and europium ions, leading to a material which can act as an efficient and stable dual-emission sensor.

中文翻译：

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双发射铕掺杂ZIF-8粒子的形态、结构和光物理特性研究

摘要 具有协同特性的功能材料的开发，包括基于金属有机骨架 (MOFs) 的荧光探针和具有双发射的镧系元素离子，引起了科学界的兴趣。在这方面，通过简单快速的方法在室温 (25 °C) 下制备了一系列含有铕离子的 ZIF-8 材料（ZIF-8:x% Eu，其中 x = 1、3 或 7%）和评估了结构、形态和光物理特性。结果表明，铕离子的插入使结晶度从 ZIF-8 的 71% 降低到 ZIF-8:1% Eu、ZIF-8:3% Eu 和 ZIF-8 的 67%、54% 和 32%分别为：7% Eu。尽管如此，ZIF-8 的晶体结构仍保持不变，仅观察到平面中的小位移，这可归因于在 MOF 结构的锌位中取代了铕离子。一般来说，与未掺杂的 ZIF-8 相比，铕离子的存在提高了热稳定性并降低了表面积。Eu 掺杂的 ZIF-8 的发射光谱揭示了与 ZIF-8 发射相关的蓝色区域的信号和配位聚合物中 Eu3+ 离子的谱线，这与具有双发射的异质结构材料的形成一致. 此外，铕 ff 跃迁的强度随着 Eu3+ 的量增加，表明这种能量转移的效率增加。这项研究提供了一个基于 ZIF-8 和铕离子协同特性开发双发射 MOF 的进展示例，