用于低温区域自校准荧光温度传感的双核稀土－有机框架材料

本项目拟选用发光性能优良且能产生能量传递的稀土离子（如Eu3+和Tb3+、Er3+和Yb3+等）作为双金属中心，与刚性羧酸配体组装构筑双核稀土－有机框架材料。利用不同稀土发光中心之间的温敏传能过程使荧光强度比值与温度建立关联，开展双核稀土－有机框架材料在低温区域的自校准荧光温度传感研究，通过稀土离子种类、比例以及有机配体分子结构、配位构型和电子能级的调变来控制稀土离子之间的能量传递过程，从而实现框架材料发光效率、温度响应区间和灵敏度的调控和优化。本项目研究将建立完善双核稀土－有机框架材料的设计思路与定向组装方法，揭示不同温度下框架材料中的电子转移、能量传递及其机制，获得不同基元之间能量传递过程的调控方法及其与测温范围、灵敏度的关联规律，为低温区域的荧光温度传感提供设计思想、关键材料和制备方法，同时也为拓展金属－有机框架材料的环境荧光探测提供新的方法和途径。

This proposal intends to prepare mixed-lanthanide metal-organic frameworks (MOFs) using Eu3+, Tb3+, Er3+ and Yb3+ as metal center. The temperature-dependent energy transfer between lanthanide ions will result in the variation of luminescent intensity ratio, which make the MOFs could be used in the self-referencing luminescent temperature sensing in cryogenic region based on intensity ratio. The energy transfer between lanthanide ions could be tuned by modifying the type and ratio of lanthanide ions, the molecular structure of organic ligands, coordination geometry and electronic energy levels of the MOFs. In particular，the richness of organic linkers to tune their different triplet excited state energy and thus to sensitize different combination of lanthanide ions and to construct diverse MOF structures to optimize the energy transfer among the lanthanide ions could enable the mixed lanthanide MOFs approach to realize practically useful luminescent thermometers with high sensitivity and a tunable response range. Through the implementation of this proposal, the design theories and controllable assembly of lanthanide MOFs will be established, the energy transfer and its mechanism at different temperatures will be investigated, the relationship between energy transfer process and the temperature response range, sensitivity will be discovered, as well as the design theories, critical materials and assembly methods of lanthanide MOFs for luminescent cryogenic temperature sensing will also be obtained.