新型石墨烯及类石墨烯量子点的制备及应用

发布时间：2018-02-15 06:34

本文关键词： 石墨烯量子点氮化硼量子点二硫化钼量子点细胞成像　出处：《青岛大学》2017年硕士论文　论文类型：学位论文

【摘要】：在本文中我们合成并研究了三种新型石墨烯及类石墨烯量子点,一种是基于碱性乙醇电解液的电化学氧化石墨电极法制备石墨烯量子点,一种是采用超声加溶剂热的方法用三种不同的有机溶剂将块状氮化硼变为氮化硼量子点,一种是以硫化钠和氯化钼为前驱体,在溶剂热下得到了二硫化钼量子点。石墨电极在碱性乙醇溶液中发生电化学氧化,产生石墨烯量子点,生成的石墨烯量子点的平均直径是4.0±0.2 nm,并且具有很好的结晶性,反应后的石墨烯量子点的分散液为无色,但在室温下保存时分散液会由无色逐渐变成亮黄色。根据高分辨透射电镜(HRTEM)、紫外-可见光(UV-Vis)吸收光谱、傅里叶变换红外光谱(FTIR)、X射线光电子能谱(XPS)及荧光光谱,我们对石墨烯量子点的颜色变化进行了分析和解释,即由于随着时间的推移,表面官能团的氧化。此外,生成的石墨烯量子点可用于三价铁离子的特异性检测,最低检测线为1.8μM(S/N=3);同时,我们也证明了自来水中铁离子的检测可用此量子点进行。基于其低毒性和优良的生物相容性,所制备的石墨烯量子点被成功应用于细胞成像研究。采用超声加溶剂热的方法用不同的有机溶剂(乙醇,N,N-二甲基甲酰胺,1-甲基-2-吡咯烷酮),采用乙醇和N,N-二甲基甲酰胺作溶剂,得到的氮化硼量子点在紫外灯照射下发出很亮的蓝色光,而采用1-甲基-2-吡咯烷酮作溶剂,得到的氮化硼量子点在紫外灯照射下呈现绿光。采用这三种溶剂得到的氮化硼量子点的荧光产率和直径分别为12.6%与4.1±0.2 nm,16.4%与2.8±0.3 nm,以及21.3%与2.0±0.2 nm;我们发现得到的量子点的荧光产率、平均直径和光学性质与所用溶剂的极性有很大的关系。此外,得到的这三种不同的氮化硼量子点具有广泛的用途,例如当作为荧光传感器检测金属离子时发绿光的量子点能够更好地用于三价铁离子的检测;而用乙醇作溶剂得到的发蓝光的量子点更适合用于细胞成像和纤维染色研究。更重要的是,我们第一次发现并研究了氮化硼量子点的电化学发光情况,其共反应剂为L-半胱氨酸;我们也提出了氮化硼量子点发光可能的机理。以硫化钠和氯化钼为前驱体,采用溶剂热方法合成了二硫化钼量子点。制备出的二硫化钼量子点的平均直径为1.8±0.2 nm,具有光稳定性,低毒性并且在365 nm紫外灯下发出很亮的蓝色光。我们提出了合成二硫化钼量子点的可能的机理并给予了系统的研究。此外,基于其低毒性和良好的生物相容性,它们被成功的应用于细胞成像的研究。
[Abstract]:In this paper, we have synthesized and studied three new graphene and graphene like quantum dots. One is electrochemical oxidation graphite electrode method based on alkaline ethanol electrolyte to prepare graphene quantum dots. One is to convert boron nitride into boron nitride quantum dots in three different organic solvents by ultrasonic and solvothermal method, and the other is to use sodium sulfide and molybdenum chloride as precursors. Molybdenum disulfide quantum dots were obtained by solvothermal method. The graphite electrode was electrochemical oxidized in alkaline ethanol solution to produce graphene quantum dots. The average diameter of the resulting graphene quantum dots was 4.0 卤0.2 nm and had good crystallinity. The dispersions of graphene quantum dots after reaction are colorless, but when stored at room temperature, the dispersions change from colorless to bright yellow. According to the high resolution transmission electron microscope (TEM) HRTEMN, UV-Vis-UV absorption spectra, Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) and fluorescence spectra, we have analyzed and explained the color changes of graphene quantum dots, that is, the oxidation of surface functional groups over time. The resulting graphene quantum dots can be used for the specific detection of trivalent iron ions, with a minimum detection line of 1.8 渭 m ~ (-1) S / N ~ (3 +). At the same time, we have also demonstrated that the detection of iron ions in tap water can be carried out by this quantum dot, based on its low toxicity and excellent biocompatibility. The prepared graphene quantum dots have been successfully used in cell imaging. Different organic solvents (ethanol, N-dimethylformamide, 1-methyl-2-pyrrolidone), ethanol and N-dimethylformamide were used as solvents. The resulting boron nitride quantum dots emit very bright blue light under the irradiation of an ultraviolet lamp, while 1-methyl-2-pyrrolidone is used as solvent. The fluorescence yields and diameters of boron nitride quantum dots obtained by using these three solvents were 12.6% and 4.1 卤0.2nmg ~ (16)% and 2.8 卤0.3nm, respectively, and 21.3% and 2.0 卤0.2nm ~ (-1) respectively. We found that the fluorescence yield of the quantum dots was 21.3% 卤0.2nm. The average diameters and optical properties are greatly related to the polarity of the solvents used. In addition, the three different boron nitride quantum dots have a wide range of applications. For example, quantum dots that emit green light when detecting metal ions as fluorescence sensors can be better used in the detection of trivalent iron ions. However, the blue-emitting quantum dots with ethanol as solvent are more suitable for cell imaging and fiber dyeing. More importantly, we first discovered and studied the electrochemical luminescence of boron nitride quantum dots. The possible luminescence mechanism of boron nitride quantum dots was also proposed. Sodium sulphide and molybdenum chloride were used as precursors. Molybdenum disulfide quantum dots were synthesized by solvothermal method. The average diameter of the prepared quantum dots is 1.8 卤0.2 nm. The mechanism of synthesis of molybdenum disulfide quantum dots has been proposed and systematically studied. In addition, due to its low toxicity and good biocompatibility, They have been successfully applied to the study of cell imaging.
【学位授予单位】：青岛大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB383.1;O613.71

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