介孔限域构建低温稳定立方相钙钛矿量子点复合微球及生物检测研究

Perovskite quantum dots have tunable photoluminescence that is capable of covering the entire visible spectrum and have high quantum yields, which make them a new fluorescent material for various applications. However, their poor stability limits their development and large-scale application. The novel method of confined reaction process for fabrication of perovskite quantum dots embedded in mesoporous silica microspheres will be developed in this project. Furthermore, poly (methyl methacrylate) (PMMA) will be further coated on the surface of the composite microspheres via atom transfer radical polymerization (ATRP), which can maintain the long-term stability in the aqueous phase due to the dense coating layer. Finally, these composite microspheres will be used in the field of ultra-sensitive detection of trypsin by fluorescence resonance energy transfer through perovskite quantum-dot to polypeptide chain (CF6(Cys-Pro-Arg-Gly-R6G)). The morphology and structure of perovskite quantum dots in mesoporous channels are controlled by different polar solvents, surface ligands and reaction temperatures. And their kinetic process of nucleation and growth in the confined pore space was revealed. The microscopic mechanism for formation and growth of perovskite quantum dots embedded in mesoporous silica microspheres in the confined system will be revealed based on the results of experimental and theoretical calculations. The type process of anion exchange reaction will be monitored by in situ fluorescence spectroscopy, and combined with the molecular dynamics simulation model. These studies will elucidate the transfer and reaction process in the mesoporous confined microenvironment of the nanocomposite microspheres, and provide valuable reference information for the nanostructures design and controllable performances of new mesoporous nanocomposite materials.

钙钛矿量子点具有窄的发射谱线、高的量子产率和全可视光光谱发射等优异光学性能，但是其稳定性比较差，这在很大程度上影响了其应用。本项目拟采用介孔限域反应过程，在二氧化硅微球介孔孔道内封装钙钛矿量子点，借助于介孔孔道限域效应提高其稳定性及其荧光性能。利用原子转移自由基聚合在复合微球表面包覆聚甲基丙烯酸甲酯实现其在水相中的长期稳定性，借助荧光共振能量转移技术实现对胰蛋白酶的超高灵敏度的检测。利用钙钛矿量子点的阴离子交换反应的荧光变化特征规律，通过原位荧光谱的监测阐述介孔限域微环境下的传递和反应过程，结合分子动力学方法模拟阐明介孔孔道内传质模型结构，为新型介孔纳米复合材料的结构设计和性能调控提供有价值的借鉴信息。

本项目针对限域反应构建纳米复合材料的典型过程，构建介孔二氧化硅封装立方相钙钛矿量子点复合微球，借助介孔孔道限域效应提高其稳定性及其荧光性能。在依托单位和所在课题组的支持下，按照项目的技术路线和实施计划，通过利用介孔二氧化硅装载、原位高分子聚合包覆等技术手段实现钙钛矿量子点的稳定性的极大提升，进一步研究在不同极性溶剂、光热和氧气环境条件下的量子点的结构和光学性能的变化，揭示钙钛矿量子点失效机制，阐明钙钛矿量子点负载的复合微球的表界面微观结构对量子点光电性能的构效关系，并发现该材料在光催化、光电探测器、生物显影等领域的应用前景，为新型钙钛矿量子点材料的推广应用提供借鉴。经过四年的项目执行，已经完成相关合同和课题任务书中的考核指标。通过液相合成和高温熔融两个工艺制备了介孔SiO2微球负载钙钛矿量子点复合材料，基于介孔孔道作为微反应器，通过限域反应实现了粒子间的间隔与分离，采用共轭亚油酸作为量子点表面配体，利用量子点作为光引发剂，在光照条件下引发了共轭亚油酸的自由基聚合，实现了聚合物对钙钛矿量子点复合微球的包覆。相关技术指标均已完成，申请发明专利4项，其中授权发明专利2项，标注发表SCI论文23篇，培养研究生4名。项目负责人入选2020年入选上海市东方学者计划，2020年作为第五完成人获得国家自然科学奖二等奖。