基于氧气荧光探针的量子点/金属有机框架纳米复合材料的可控合成及性能研究

Metal-organic framework (MOF) as a new type of microporous material has potential applications in the field of analytical chemistry. Although many reports about MOF based ion and organic molecule sensors have been reported, MOF based gas sensors have been rarely developed because of the weak interaction between gas molecules and low sensitivity. The selective adsorption of gas on MOF and the rapid optical response of gas on QDs make the QD/MOF composite a promising candidate for the gas sensor. On the other hand, the detection of O2 is very important in the areas such as environmental monitoring, biological analysis and industrial analysis. Hereby, the preparation of nano-sized QD/MOF composites by the assembly of metal ions and organic ligands on the surface of modified QDs is proposed in this project. Through the investigation on the assembly of metal ions and organic ligands on the functionalized QDs, the principles of the controllable synthesis of QD/MOF for O2 detection will be extensively researched. The accomplishment of this project will provide theoretical and technical supports for the controllable synthesis of nano-particles/MOF composites, especially for QD/MOF. At the same time, the serious restriction to the development of QDs based gas sensors can also be solved, providing new ideas for the application of both MOFs and nano-particles.

金属有机框架(MOF)作为一种新型多孔材料在分析化学领域具有潜在的应用前景，然而气体分子难以激发MOF材料光电响应的本质限制了基于MOF材料的高灵敏度气体传感器的发展。量子点/金属有机框架纳米复合材料(QD/MOF)因兼具MOF对气体分子的选择性吸附富集特性和量子点对气体的快速光学响应机制而有望解决这一难题。据此，本项目拟将荧光量子点引入MOF材料，设计合成基于O2探针的QD/MOF纳米复合材料。研究采用量子点表面功能化修饰，有机配体与金属离子的层层自组装、以及光学检测等方法，探讨金属离子和有机配体在量子点表面的组装原理、QD/MOF的可控合成途径、以及QD/MOF对气体的吸附及光学响应机制。据此阐明针对O2分子检测要求的金属离子和有机配体在功能化量子点表面的组装策略。本研究的成功为实现基于QD/MOF材料的气体检测提供理论基础，同时为拓展MOF材料的应用提供一条新思路。

量子点因具有发光强度高及荧光波长可调等特点而受到广泛关注，并已经发展成为可以代替有机染料被应用于新型荧光探针及敏化太阳电池开发中。本项目首先采用双配体水相合成或SiO2表面包覆法合成高质量水溶性量子点。基于物种诱导淬灭的量子点荧光恢复原理，设计合成量子点荧光探针，实现了对水环境中生物巯基高选择性和高灵敏性检测。进一步将该荧光探针做成了试纸，从而简化了传统方法对生物巯基检测程序。同时，设计合成系列多孔MOF材料，并研究其对气体小分子吸附性能。此外，我们将量子点应用拓展至光电转换领域，制备量子点敏化太阳电池。针对传统电解液易泄露难封装等问题，采用具有超强吸水及锁水性能的聚电解质，使聚硫电解液凝胶化，制备准固态量子点敏化太阳电池，取得了9.21%的光电转换效率，为同期该类电池的最高转换效率。本项目取得的成果为设计合成量子点荧光探针，气体分子吸附存储及敏化太阳电池等提供了理论基础和技术支持。