稀土发光材料/碳量子点复合材料的制备、发光性能及能量传递机制

Composite material is a kind of very important heterogeneous solid material in the National Development Strategy and the field of materials science, because its function can be designed and integrated the advantages of each component material. Rare earth luminescent materials and carbon quantum dots (CQDs) are two kinds of luminescent materials with different features. The former has many advantages such as multi-color emission, line spectrum, high color purity, long lifetime, etc. As for the latter, it is considered as a kind of star material in the carbon family and has been paid extensive attention in recent years. CQDs have excellent water-soluble and biocompatible properties, and their photoluminescent emission band is dependent on the wavelength of excitation spectrum and the lifetime is at the nanosecond scale. In this project, using the design concept of supramolecular chemistry, rare earth luminescent materials/carbon quantum dots composites will be obtained through the composition of rare earth luminescent materials and CQDs, and this composites will be integrated the advantages of these two component materials. The effect of the composition route, synthesis conditions, surface functional groups, surface state, bond structure, etc. on the phase structure, morphology, bond type, water-solubility, biocompatible and luminescence properties of the obtained composites will be investigated systematically. According to above investigations, the composition mechanism of rare earth luminescent materials and CQDs will be discussed. The luminescent properties of the composite will be investigated and compared with that of the respective rare earth luminescent materials and CQDs, and the luminecence mechanism of the composites and the energy transfer between CQDs and rare earth luminescent materials will be proposed. The obtained composites will be used to establish the luminescent “turn-on” system, which might be applied as fluorescent probe in chemical and biological detection fields. Based on the experimental results and the proposed mechanism of this project to be executed, it is expected that the investigation will not only provide academic instruction in the desigh of novel composite materials and new energy transfer system, but also extend the application fields of rare earth luminescent materials and CQDs.

复合材料作为一种功能可设计、综合各组成材料优点的多相固体材料，在国家的发展战略及材料科学领域占据重要的地位。稀土发光材料和碳量子点是两类性能不同的发光材料，前者易于实现多色发光，且具有色纯度高、荧光寿命长等特点；后者具有良好的水溶性及生物相容性，其发射光谱为带状且随激发波长的改变而改变等。本项目拟将稀土发光材料与碳量子点进行复合，得到综合二者优点的稀土发光材料/碳量子点复合材料。研究复合路线、合成条件、表面功能基团、价键结构、表面态等对复合材料相结构、形貌、成键类型、水溶性、生物相容性、发光性能的影响，探讨材料的复合机制；系统研究复合前后材料的发光性能，探讨复合材料的发光机理及碳量子点、稀土发光材料之间的能量传递机制；构建具有荧光“开关”功能的发光体系，探讨其在化学、生物传感等方面的应用。该研究不但为设计新型复合材料、构建新的能量传输体系提供理论指导，也有望进一步拓宽这两类材料的应用领域。

稀土发光材料和碳量子点是两类性能不同、且具有重要应用价值的发光材料。本项目主要将稀土发光材料与碳量子点进行复合，得到性能更加优异的稀土发光材料/碳量子点复合材料。已完成的主要研究内容有：（1）稀土离子掺杂的钨酸盐发光材料/碳量子点复合材料。制备出具有三维花状的MgWO4:Eu3+/碳量子点复合材料、二维的MgWO4: Ln3+ (Ln = Eu, Tb)/碳量子点复合纳米片、以及Yb3+、Er3+共掺杂的AWO4 (A = Ca, Sr, Ba)/碳量子点复合上转换发光材料，碳量子点的复合可显著提高其发光性能，提出了碳量子点与稀土发光材料之间的能量传递机制，阐明了发光性能提高的内在原因。（2）Yb3+, Er3+/Tm3+共掺杂的NaYF4/碳量子点复合材料。将立方体状的荧光碳纳米颗粒分别与具有不同形貌（纳米颗粒、纳米棒状、纳米管状）的上转换发光材料NaYF4:Yb3+,Er3+及NaYF4:Yb3+,Tm3+进行复合，对于不同形貌的纳米颗粒、棒状、管状上转换发光材料，碳点复合后其上转换发光性能均明显增强，其中以管状的材料增强最为显著。（3）YBO3:Eu3+微球/碳量子点复合材料。合成了发光性能优异的CDs@YBO3:Eu3+复合物，碳量子点的复合可显著提高YBO3:Eu3+微球的发光性能，这主要是由于碳量子点与掺杂Eu3+之间发生了有效的荧光共振能量传递所致。此外，还合成了稀土配合物复合材料体系并研究了其发光性能、具有药物控制释放性能的多功能稀土复合材料NaYF4:Yb/Er@SiO2@PMAA及NaYF4:Yb,Er@mSiO2-PAA、以及多功能复合纳米纤维并探讨其在组织工程等生物医学领域的应用。项目执行期间共发表SCI收录论文37篇，获授权中国发明专利4件，培养硕士研究生4名。