碳量子点的制备及其荧光传感应用研究

发布时间：2018-04-02 00:29

本文选题：碳量子点　切入点：氮掺杂　出处：《华侨大学》2017年硕士论文

【摘要】：碳量子点(CQDs),具有了优越的光电性能、良好的水溶性和生物相容性,并且制备方法简单,使其在化学传感、生物成像等方面具有巨大的应用潜力。本文基于它的卓越性能,从制备出发,通过不同前驱体,以掺杂杂原子的方式制备获得不同性能的CQDs,并探索该些材料在荧光传感和细胞成像方面的应用。具体研究内容如下:1、本文利用微波法制备得到氮掺杂碳量子点(NCQDs)。通过透射电镜(TEM)、X射线能谱仪(EDS)、光电子能谱仪(XPS)和傅里叶红外光谱仪(FTIR)对其形貌、结构和组分进行表征,结果表明所纯化出的NCQDs,平均粒径约为4.0 nm,表面含有丰富的含氧含氮基团,因此是一种氮掺杂的碳纳米材料。通过紫外分光光度计和荧光分光光度计对NCQDs光学性能进行表征,结果显示NCQDs的紫外吸收在245 nm和339 nm,其荧光发射峰具有波长依赖性,最大荧光激发和发射峰分别为383 nm和457 nm。此外,该材料的荧光发射峰还具有pH依赖性和良好的环境稳定性。由于3,5-二硝基水杨酸对NCQDs荧光表现出强烈的荧光猝灭响应,因此,构建了基于NCQDs荧光探针的3,5-二硝基水杨酸的荧光检测方法,并对该检测体系进行优化。结果表明,3,5-二硝基水杨酸对NCQDs猝灭的程度与其浓度在1μmol/L~100μmol/L内呈良好的线性关系(R2=0.9976),检测限为0.68μmol/L(S/N=3)。同时,初步讨论3,5-二硝基水杨酸对NCQDs荧光的猝灭机制。2、在前一个实验的基础上,我们改变前驱体,以柠檬酸和半胱氨酸为前驱体,用微波法制备得到高荧光量子产率的氮硫共掺杂的碳量子点(NSCQDs)。用TEM对其形貌进行表征,结果表明NSCQDs为近球形,其平均粒径约为2.2nm。FTIR结果表面该材料表面含有含氧、含氮、含硫基团,证明其属于氮硫双掺杂的碳纳米材料。光学表征结果显示,该材料在紫外可见范围内有三个吸收峰,分别处于212、244和348 nm;其最佳荧光激发和发射波长分别为356 nm和423 nm,荧光量子产率可达61.41%,并且荧光发射波长不会随着激发波长的改变而移动,但是具有浓度依赖性和一定范围的pH稳定性。此外,该材料的发光性能同样具有良好的环境稳定性和生物相容性,因此,我们探索了该材料在细胞成像和荧光“油墨”笔方面的应用。
[Abstract]:Carbon quantum dots (CQDs), with excellent optoelectronic properties, good water solubility and biocompatibility, and the preparation method is simple, the chemical sensing, have great potential applications in bio imaging and so on. In this paper, based on its superior performance, from the preparation of the precursor, to doped heteroatom to prepare and obtain the different performance of CQDs, and to explore the application of these materials in fluorescence sensing and cell imaging. The specific contents are as follows: 1, using microwave prepared nitrogen doped carbon quantum dots (NCQDs). By transmission electron microscopy (TEM), X ray spectrometer (EDS), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectrometer (FTIR) on the morphology, structure and composition were characterized. The results show that the purified NCQDs, the average particle size is about 4 nm, the surface rich in oxygen nitrogen group, it is a carbon nano material doped with nitrogen Material. Spectrophotometer was used to characterize the optical properties of NCQDs by UV spectrophotometer and fluorescence results show that the UV absorption of NCQDs at 245 nm and 339 nm, the fluorescence emission peak with the wavelength dependence of the maximum fluorescence excitation and emission peaks were 383 nm and 457 nm. in addition, the fluorescent material the emission peak is pH dependent and good environmental stability. Because of the 3,5- two nitro salicylic acid on NCQDs fluorescence showed strong fluorescence quenching response, therefore, constructs the fluorescence detection method of NCQDs fluorescent probe 3,5- two nitro salicylic acid based, and the detection system were optimized. The results showed that 3,5- two nitro salicylic acid degree the NCQDs quenching of a good linear relationship with its concentration in 1 mol/L~100 mol/L (R2=0.9976), the detection limit was 0.68 mol/L (S/N=3). At the same time, a preliminary discussion of 3,5- two nitro salicylic acid quenching mechanism of the fluorescence of NCQDs.2 In the previous experiment, based on, we change the precursor with citric acid and cysteine as the precursor, carbon quantum dots were prepared by microwave with high fluorescence quantum yield of sulphur and nitrogen Co doped (NSCQDs). The morphology was characterized by TEM, the results showed that NSCQDs was nearly spherical, the average the size is about 2.2nm.FTIR the surface of the material containing oxygen, nitrogen, sulfur groups, carbon nano materials that it belongs to the nitrogen and sulfur doped. The optical characterization results show that the material has three absorption peaks in the UV visible range, respectively in 212244 and 348 nm; the optimal excitation and emission the wavelength was 356 nm and 423 nm, the fluorescence quantum yield of up to 61.41%, and the fluorescence emission wavelength doesn't move when the excitation wavelength is changed, but pH has concentration dependent stability and a certain range. In addition, the material has the same luminous performance Good environmental stability and biocompatibility, therefore, we have explored the application of the material in cell imaging and fluorescence "ink" pen.

【学位授予单位】：华侨大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O613.71;TB383.1

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