杂原子共掺杂碳点的制备及其荧光机理研究

Carbon nanodots (C-dots) have atracted great attention and become the hotspot of research due to their superior solubility, chemical inertness, low toxicity, biocompatibility and ease of functionalization. Although N-doped carbon nanodots have been currently the foucus of the doped C-dots related research, the synthesis and fluorescence mechanism of the heteroatom including sulphur/nitrogen(S/N), phosphorus/nitrogen(P/N) and boron/nitrogen(B/N) co-doped C-dots have been rarely reported so far. In this project, we first propose to synthesize the B/N and P/N co-doped C-dots using ionic liquid, amino acid, boron nitride and biomass as precursors via hydrothermal synthsis, high-temperature calcination etc.. A series of novel co-doped C-dots with B/N and P/N will be subsequently synthesized by changing the ratio of the precursors like the ratio of heteroatom so as to regulate their fluorescence properties. The composition, structure and proportions of their chemical bonds of the heteroatom co-doped C-dots will be well characterized with infrared spectrum, Raman spctrum and X-ray photoelectron spectroscopy. Also, the influence of heteroatoms on the electronic properties, surface and local chemical reactivities will be explored in detail which we believe can provide theoretical support for the mechanism of fluorescence generation in the future. This project may provide new ideas to the synthesis of the heteroatom co-doped C-dots and the improvement of their fluorescence properties and offer a promising platform for the fabrication of photochemical sensors.

碳点由于具有良好的水溶性、化学稳定性、低毒性、生物相容性以及易于修饰等优点，已经逐渐成为研究的热点。目前掺杂碳点的研究主要集中在氮掺杂，而杂原子（如硫氮、磷氮、硼氮等）共掺杂碳点的制备及其荧光机理的研究较少，基本属于空白。本项目拟以离子液体、氨基酸、硼氮化合物以及生物质为原料，采用水热、高温煅烧等手段制备新型硼氮、磷氮共掺杂碳点。通过调整不同前驱体的比例（调整杂原子的比例），制备一系列新型硼氮、磷氮共掺杂碳点，以期达到调控所制备共掺杂碳点荧光性能的目的。拟借助红外、拉曼、X-射线光电子能谱以及荧光等手段研究碳点的组成、结构以及化学键的构成、比例，探索杂原子的掺杂对碳点的电子性能、表面和局部的化学反应活性的影响，为进一步理解荧光的产生机理提供理论支持。本课题的研究将为杂原子共掺杂碳点的制备及其荧光性能的改进开辟新的思路，所制备的碳点也为建立光化学传感器提供良好的平台。

碳点由于具有优异的性能，已经逐渐成为研究的热点。目前掺杂碳点的研究主要集中在氮掺杂，而杂原子共掺杂碳点的制备及其荧光机理的研究较少，基本属于空白。本项目首先以离子液体、氧化石墨烯、尿素和硼酸等为原料，采用水热法先后制备了氯氮共掺杂碳点、硫氮共掺杂碳点以及硼氮共掺杂碳点。借助于红外光谱、拉曼光谱、X-射线光电子能谱以及荧光光谱等现代技术手段研究了所制备碳点的组成、结构和荧光性能。结果表明：所制备的碳点均具有近似球形纳米结构，且分散均匀；此外，碳点还具有良好的荧光稳定性、高的抗漂白性、良好的水溶性、低毒性和良好的生物相容性。其次，在成功制备了硼氮共掺杂碳点的基础上，通过调整尿素和硼酸的比例，又制备了一系列不同类型的硼氮共掺杂碳点。研究了硼和氮的掺杂对所制备的共掺杂碳点的结构、化学键的构成和比例的影响，进而研究了结构对荧光性能的影响，并推测出了所制备的硼氮共掺杂碳点的荧光机理。结果表明：随着硼和氮含量的增加，不同类型的硼氮共掺杂碳点的结构不同，且晶格结构趋于有序；并随着碳点中硼-氮键含量的增加，不同类型的硼氮共掺杂碳点的荧光发射波长蓝移，推测出硼氮共掺杂碳点可调的荧光特性可能源于不同的表面状态。最后，我们还研究了所制备碳点的应用，结果表明不同条件下制备的碳点对离子检测具有特异性。本课题的研究为杂原子共掺杂碳点的制备及其荧光性能的改进开辟新的思路，所制备的碳点也为建立光化学传感器以及生物检测提供良好的平台，其研究内容丰富，具有广阔的应用前景。