石墨烯量子点、氮掺杂石墨烯量子点的制备及性能研究

发布时间：2018-05-09 14:05

本文选题：柠檬酸 + 尿素　；参考：《西北大学》2015年硕士论文

【摘要】：近年来,随着科学技术的发展,低维碳纳米材料逐渐被人们所发现。尤其是从石墨中剥离出单层的二维石墨烯之后,石墨烯材料的特性及应用很快成为各领域科学家们研究的热点。准零维材料中的量子点随着其制备技术的不断提高,已经被逐渐应用于荧光探针、细胞成像等生物和医学方面。作为一种新兴的碳材料—石墨烯量子点(graphene quantum dots, GQDs),不仅具有石墨烯的导电性良好、强度大、比表面积大等优异特性；而且结合了量子点的量子限域效应、小尺寸效应及边缘效应等优点,表现出良好的生物相容性、低毒性、强水溶性、高荧光稳定性等特性,使其在生物医药、传感器、光学及电学器件等方面有潜在的应用前景。本论文主要优化改进制备GQDS及其氮掺杂的条件,以提高其荧光量子产率,通过各种手段对材料的结构及性质进行了详细研究,并探究了氮掺杂石墨烯量子点(N-GQDs)在离子检测中的应用以及GQDs在HBV-DNA检测中的应用。全文主要研究内容为以下几部分：(1)采用热解法,以柠檬酸为有机前驱体,制备石墨烯量子点,通过优化反应时间、反应温度、溶液酸碱度等实验条件,探究最优的制备条件。在最优条件下,其荧光量子产率达到9%,平均粒径为3.0 nm。并以尿素为氮源,利用水热法对GQDs实施氮掺杂制备了富含“吡咯N”的N-GQDs,通过研究原料配比、反应时间和反应温度等因素对荧光性能的影响确定了实验优化方案。在最优化条件下,其荧光量子产率为24%,平均粒径为7.5 nm。与此同时,GQDs (τ1=1.74 ns)和N-GQDs (τ1=7.40 ns)的荧光寿命衰变被很好的拟合成一条单指数曲线,说明二者都具有单一发色源。除此之外,我们还对GQDs及N-GQDs的形成机理进行了详细讨论。(2) N-GQDs构建光致发光传感器检测Cu2+。Cu2+与N-GQDs表面的羧基进行化学螯合,使得N-GQDs发生聚集,导致能量或电子的转移,使N-GQDs的荧光发生猝灭。Cu2+浓度与荧光强度在0～100 nM范围内呈线性关系,检出限为14 nM。此检出限比先前报道过的一些值更有意义。(3)以GQDs作为荧光供体,GO作为荧光受体构建检测HBV-DNA方法。研究了GO浓度、响应时间及加入目标DNA(tDNA)后的孵化时间等因素对HBV-DNA检测的影响。在最佳条件下,体系荧光强度的恢复比率约96.5%,检出限达5.08 nM(S/N=3)。该检测方法可以高效分辨完全互补序列、单碱基错配序列和完全不互补序列,方法简便、灵敏度高,具有极大的应用价值。
[Abstract]:In recent years, with the development of science and technology, low-dimensional carbon nanomaterials have been gradually discovered. Especially after the removal of two-dimensional graphene from graphite, the properties and applications of graphene materials have quickly become the focus of scientists in various fields. Quantum dots in quasi-zero dimensional materials have been gradually used in biological and medical fields such as fluorescent probes cell imaging and so on with the improvement of their preparation techniques. As a new carbon material, graphene quantum Dots (GQDsN) not only have good electrical conductivity, high strength and large specific surface area of graphene, but also combine the quantum limiting effect of quantum dots. The advantages of small size effect and edge effect, such as good biocompatibility, low toxicity, strong water solubility and high fluorescence stability, make it have potential applications in biomedicine, sensors, optical and electrical devices. In order to improve the fluorescence quantum yield of GQDS and its nitrogen doping, the structure and properties of GQDS were studied in detail. The application of N-doped graphene quantum dots (N-GQDs) in ion detection and the application of GQDs in HBV-DNA detection were also discussed. The main contents of this paper are as follows: 1) the optimum preparation conditions of graphene quantum dots were investigated by optimizing the experimental conditions such as reaction time, reaction temperature and pH of the solution, using citric acid as an organic precursor. Under the optimum conditions, the fluorescence quantum yield is 9 and the average particle size is 3.0 nm. N-GQDsrich in pyrrole N were prepared by hydrothermal method with urea as nitrogen source. The optimum scheme was determined by studying the effects of raw material ratio, reaction time and reaction temperature on the fluorescence properties of N-GQDsrich in GQDs. Under the optimum conditions, the fluorescence quantum yield is 24% and the average particle size is 7.5 nm. At the same time, the fluorescence lifetime decay of GQDs (蟿 1, 1. 74 ns) and N-GQDs (蟿 1 + 7. 40 ns) were well fitted into a single exponential curve, indicating that both of them have a single chromogenic source. In addition, we also discussed the formation mechanism of GQDs and N-GQDs in detail. The photoluminescence sensor constructed by N-GQDs was used to detect the chemical chelation of Cu2. Cu2 with the carboxyl group on the surface of N-GQDs, which led to the aggregation of N-GQDs and the transfer of energy or electrons. The fluorescence quenching of N-GQDs shows a linear relationship with fluorescence intensity in the range of 0 ~ 100nM, and the detection limit is 14 nm. The detection limit is more significant than some previously reported values.) GQDs was used as a fluorescent donor and go as a fluorescent receptor to construct a method for the detection of HBV-DNA. The effects of go concentration, response time and incubation time on HBV-DNA detection were studied. Under the optimum conditions, the recovery ratio of fluorescence intensity of the system is about 96.5 and the detection limit is 5.08 NM / S / N ~ (3 +). The method is simple and sensitive and has great application value because it can efficiently distinguish complete complementary sequence, single base mismatch sequence and complete uncomplementary sequence.
【学位授予单位】：西北大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ127.11

【相似文献】