煤基碳量子点的制备及荧光性能研究

发布时间：2018-01-26 22:56

  本文关键词： 碳量子点(CQDs) 硝酸氧化 微波法 渗析 荧光量子产率(QY)　出处：《中国地质大学(北京)》2017年硕士论文　论文类型：学位论文

【摘要】：迄今为止应用最广的是金属半导体量子点,且广泛应用于电子器件和量子计算等领域,而该量子点存在的最大弊端是有较大的毒性,制备成本较高,因此科学家们尝试寻找一种可以取代的新型量子点即碳量子点。碳量子点的直径在20nm左右。而碳量子点最大的优点在于低毒性、良好的生物相容性,较强的发光性、以及光稳定性,可广泛应用于生物传感器及生物分子的检测、细胞成像等。在此基础上,为了制备碳量子点开始寻找丰富的原料,煤炭是我国的主要能源,依据结构和组成不同,煤炭分为无烟煤、烟煤、褐煤三大类,其中烟煤分为低变质烟煤、中变质烟煤,其中低变质烟煤和褐煤一起统称为低阶煤。因为目前为止对于低阶煤结构的认知还没有准确的结论,而且其种类繁多导致结构也会相应不同,因此低阶煤的研究以及应用是目前一个很重要的课题。论文通过硝酸氧化法和微波消解法制备碳量子点,研究了不同产地的低阶煤制备碳量子点的工艺,优化温度、时间、酸浓度、提纯等实验条件,发现龙口脱灰煤效果较好,反应温度为130℃,反应时间为12h。通过红外(FTIR)、碳核磁共振(13CNMR)、X射线衍射(XRD)、光电子能谱(XPS)、透射电镜(TEM)、原子力显微镜(AFM)、拉曼光谱(Raman)、荧光光谱(PL)等,表征了碳量子点的结构(粒径、官能团等)和性质。并表征了碳量子点在激光下激发下的荧光。提出煤与硝酸反应生成CQDs的机理:除了煤大分子的硝化的过程,同时还伴随Scholl反应导致的芳香簇稠并过程。分别用聚乙二醇(PEG)、超酸(双(三氟甲烷)磺酰亚胺TFSI)改性碳量子点,发现改性后荧光量子产率提高。利用碳量子点制备出有荧光性质的静电纺丝PVA膜和荧光墨水,得到了较好的效果。
[Abstract]:So far the most widely used metal semiconductor quantum dots, and widely used in electronic devices, quantum computing and other fields, and the biggest disadvantage of this quantum dot is that it has greater toxicity and high cost of preparation. So scientists try to find a new quantum dot which can be replaced by carbon quantum dot. The diameter of carbon quantum dot is about 20nm. The biggest advantage of carbon quantum dot is its low toxicity and good biocompatibility. Because of its strong luminescence and photostability, it can be widely used in biosensors and biomolecules detection, cell imaging and so on. On this basis, we began to search for rich raw materials for the preparation of carbon quantum dots. Coal is the main energy in China. According to the structure and composition, coal is divided into anthracite, bituminous coal and lignite, among which bituminous coal is divided into low metamorphic bituminous coal and medium metamorphic bituminous coal. Low metamorphic bituminous coal and lignite are referred to as low rank coal together, because there is no accurate conclusion about the structure of low rank coal so far, and many kinds of bituminous coal lead to different structures. Therefore, the research and application of low-rank coal is a very important subject at present. In this paper, carbon quantum dots are prepared by nitric acid oxidation and microwave digestion, and the process of preparing carbon quantum dots from low-rank coal from different habitats is studied. Optimizing the experimental conditions such as temperature, time, acid concentration, purification and so on, it was found that Longkou desliming coal had better effect, reaction temperature was 130 鈩，

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