高效稀土能量迁移上转换发光及其应用研究

Energy migration upconversion (EMU) is a new type of upconversion luminescence (UCL) mechanism that is expected to have significant applications in diverse fields such as biolabeling. As compared to the conventional upconversion luminescence centers such as Er3+ and Tm3+, EMU luminescence of Eu3+ and Tb3+ is usually featured by the higher absolute quantum yield and longer photoluminescence lifetime, because of their distinct electronic energy levels. Howerver,it should be noted that an in-depth and systematical investigation of the mechanism for EMU luminescence is still lacking so far. In this project, we will synthesize a series of lanthanide ions doped high-quality core-shell structured nanoparticles that are based on the inorganic alkaline-earth metal gadolinium fluorides. The site symmetry, localized electronic energy level, excited state dynamics as well as upconversion luminescence efficiency for lanthanide ions doped core-shell nanoparticles will be systematically studied in an effort to clarify the mechanism of EMU of Eu3+ and Tb3+ and to reveal the new approaches to enhance the EMU luminescecne efficiency. The ultimate goal is to obtain high-quality core-shell nanoparticles with absolute upconversion quantum yield as high as 5%. Subsequently, one or two types of core-shell nanoparticles will be chosen and used for sensitive heterogeneous UCL and homogeneous upconversion fluorescence resonance energy transfer (UC-FRET) bioassays of urokinase-type plasminogen activator receptor (uPAR, biomarker in tumor metastasis) and alphafetoprotein (AFP, biomaker in liver cell carcinoma).

能量迁移上转换（EMU）是近年来新发现的一种上转换发光机制，预期在荧光生物标记领域具有重要的应用前景。与传统的上转换发光中心如Er3+、Tm3+等相比，EMU发光中心如Eu3+和Tb3+等由于其特殊的能级结构，具有量子产率高、荧光寿命长等优势。目前国内外对稀土EMU发光机理缺乏系统、深入研究。本项目拟以Eu3+和Tb3+等稀土掺杂碱土金属氟钆化物等关键上转换纳米发光材料为研究对象，在实现高质量核壳结构纳米晶可控制备的基础上，系统研究稀土离子在该类材料中的位置对称性、局域态电子结构、激发态动力学以及上转换发光效率，阐明稀土EMU发光机理，揭示提高稀土EMU发光效率的新途径，获得绝对量子产率大于5%的上转换纳米发光材料1-2种。在此基础上，发展基于稀土EMU纳米荧光探针的上转换荧光异相检测和上转换荧光共振能量传递均相检测方法，实现对人体重要肿瘤标志物如尿激酶受体、甲胎蛋白的高灵敏特异性检测。

在项目执行期间，我们按照项目预期计划开展工作，以Eu3+和Tb3+等稀土掺杂碱土金属氟钆化物等关键上转换纳米发光材料为研究对象，在实现高质量核壳结构纳米晶可控制备的基础上，系统研究稀土离子在该类材料中的位置对称性、局域态电子结构、激发态动力学以及上转换发光效率，阐明稀土EMU 发光机理，揭示提高稀土EMU 发光效率的新途径，获得绝对量子产率大于5%的上转换纳米发光材料数种 种。在此基础上，发展基于稀土EMU纳米荧光探针的上转换荧光异相检测和上转换荧光共振能量传递均相检测方法，实现对人体重要肿瘤标志物如尿激酶受体、甲胎蛋白的高灵敏特异性检测。在J. Am. Chem. Soc.、Chem. Sci.等专业期刊发表了高影响力SCI或EI论文6篇，其中影SCI一区论文4篇，1篇入选近十年化学、材料领域ESI高被引频次（top 1%）论文。一项入选2016年“中国稀土十大科技新闻”。申请或授权国内外发明专利7项（授权5项）。协助培养了研究无机发光材料的博士研究生2名，独立培养硕士研究生1名，顺利完成了预定的工作计划。