X-射线同步辐射光技术在荧光碳点生成过程与发光机理研究中的应用研究

As a new sort of carbon-based fluorescent nanomaterials, carbon dots (CDs) have attracted much attention in recent years due to holding numerous merits, such as facile preparation, highly photophysical and chemical stability, tunable emission, good water solubility and biocompatibility. Consequently, CDs have been demonstrated many potential applications including chemo-/bio-sensing, bioimaging, theranostics, optoelectronic devices and so on. However, some of the bottleneck problems that limited further development of the CDs research field are still unclear of their formation process, chemical structure and luminescence mechanism. To solve these problems, microreactor technique will be taken as the experimental platform in this project. By taking advantages of the capabilities in precisely controlling reaction parameters and quickly screening reaction conditions of microreactor, a variety of CDs with different extents of carbonization and different fluorescent properties are firstly planned to prepare. Through combining the conventional characterization techniques, and particularly employing X-ray absorption fine structure (XAFS) and X-ray excited optical luminescence (XEOL) techniques, the fine chemical structures, surface status and emissive centers of the as-prepared CDs are going to be determined. Based on such results, the formation process, chemical structure and the structure-activity relationship of CDs could be proposed. Through the studies of this project, it will be helpful to make more clear to some of the key scientific problems in the CDs research field (e.g. formation process, chemical structure and luminescence mechanism), to boost the further development and make contributions in regulation of luminescence properties and practical applications of CDs.

荧光碳点是近年来发展起来的一类新型碳基纳米发光材料，由于具有制备过程简单、光物理化学性能稳定、发射可调、易于官能化修饰、水溶性及生物相容性好等诸多优点，在化学/生物传感、医学成像诊疗及光电器件等众多领域表现出巨大的应用潜力。然而当前限制该领域进一步发展的瓶颈问题之一是其生成过程、结构及发光机理仍不明确。为了解决这个问题，本项目拟采用微反应器系统为实验平台，利用该技术具有对反应条件精确控制和快速筛选的特点，实现不同碳化程度及不同荧光性能碳点的制备。结合常规表征手段，并特别利用X射线精细结构吸收(XAFS)与X射线激发荧光(XEOL)技术实现对所制备碳点的精细结构、表面状态与发射中心的确定，进而推断碳点的生成过程、结构与发光性能之间的构效关系。通过该项目的研究，将有助于进一步明确碳点的生成过程、结构及发光机理等该领域存在的关键科学问题，为促进碳点研究领域的发展、性能调控及实际应用做出贡献。

碳点是近年来发展起来的一类新型发光材料（荧光及磷光），由于具有制备过程简单、光物理化学性能稳定、发射可调、易于官能化修饰、水溶性及生物相容性好等诸多优点，因而在化学/生物传感、医学成像诊疗、防伪油墨及光电器件等众多领域表现出巨大的应用潜力。然而，碳点发光性能调控仍需拓展，生成过程、结构及发光机理仍有争议，这些问题限制了该领域进一步发展。本项目一方面通过优化和发展典型的碳点制备体系，制备出多色荧光及磷光碳点，结合常规表征和X射线精细结构吸收(XAFS)与X射线激发荧光(XEOL)技术分析所制备碳点的精细结构等信息，证明了碳点的表面状态、发射中心和碳化程度控制对荧光和磷光的发射波长具有重要的影响，相关研究结果为推断碳点结构与发光性能之间的构效关系具有重要意义；另一方面，发展了一种普适的碳点功能化复合方法，通过考察碳点与基质间的相互作用对复合体光学性能的影响，阐明碳点复合体余辉性能的关键影响因素，为设计、制备和调控碳点的长余辉复合体提供了参考；此外，本项目还探索了碳点在光学防伪、光动力治疗、药物负载与缓释、传感检测等领域的应用，为碳点在相关领域的应用奠定了基础。.通过本项目研究，在Angew. Chem. Int. Ed.，Nano-Micro Lett.，Small，Mater. Chem. Front.，ACS Appl. Mater. Interfaces等国际著名期刊发表科研论文14篇，申请国家发明专利4项，同时培养了博士后1名，博士生研究所1名，硕士研究生4名，圆满完成了预定的研究任务和目标。