碳量子点制备及其在荧光材料和离子检测中的应用

发布时间：2018-05-29 05:56

本文选题：微波反应器 + 碳量子点　；参考：《青岛科技大学》2017年硕士论文

【摘要】：碳量子点是一种无毒的高效荧光的纳米材料,因其制备过程简单,水溶性较好、易于功能化等优点,已经广泛应用于生物医药、生物成像、光电传感器和光催化剂等领域。本文通过普通微波反应器和单模微波反应器以L-胱氨酸为原料制备荧光强度高、稳定性好的碳量子点。实验中研究了多种因素对于碳量子点荧光性质的影响,并将其作为一种荧光材料染色棉纤维、掺杂硅橡胶、制作隐形荧光墨水以及检测金属离子。主要研究结论如下:(1)利用单模微波反应器制备的荧光碳量子点在水溶液中分散性好,外貌近乎球形,颗粒的尺寸大小不均匀,平均尺寸2-6 nm。碳量子点的水溶液在日光灯下呈现淡黄色,在365 nm紫外灯下呈现绿色荧光,最佳荧光激发波长420 nm,最大荧光发射波长505 nm,荧光量子产率为24%。萃取到有机相中的碳量子点在日光灯下为无色、紫外灯下发出蓝色荧光,最佳荧光激发波长为365 nm,最大荧光发射波长变为430 nm,在氯仿和二氯甲烷中的平均荧光量子产率为86%。无论水相还是有机相,最大发射波长位置不随激发波长的改变而变化。(2)水相中的碳点可以在4 oC冰箱中长期保存,有机相中的碳点可以在室温下长期保存。实验制备的碳量子点的荧光强度随着反应时间的延长和氢氧化钠浓度的提高均出现先增强后减弱的趋势。当胱氨酸的浓度为10%时,最佳反应温度为135-140°C,氢氧化钠在反应体系中的浓度为0.7-0.9 mol/L。水相碳量子点在很宽的pH范围内都具有荧光性质,且荧光强度随着pH的升高而变弱。(3)实验中制备碳量子点作为荧光材料能够染色脱脂棉、也能够掺杂硅橡胶,并可以制作荧光墨水。研究发现,使用水相中的碳量子点染色棉纤维的荧光不够牢固,而氯仿相中碳量子点染色的棉纤维荧光更牢固;使用水相碳量子点掺杂的硅橡胶呈现淡黄色,不透明,紫外灯下呈现强的蓝绿色荧光,使用有机相碳量子点掺杂的硅橡胶无色、透明,在紫外灯下发出蓝色荧光。使用碳量子点制备的荧光墨水,可以用于书写和喷墨打印,此种墨水在日光灯下无字迹显示,但是在紫外灯下显示较为清楚的字迹。(4)通过研究多种金属阳离子和部分阴离子对荧光碳量子点的淬灭作用发现,少数的离子对碳量子点的荧光强度几乎没有什么影响。己烷相中的碳量子点对Fe~(3+),Fe2+,Cu2+有很强的响应,水相中和有机相中的碳量子点对Fe~(3+)的荧光淬灭响应迅速。当Fe~(3+)的浓度在100μmol/L内水相中的碳量子点的荧光淬灭显示明显的线性关系;当Fe~(3+)的浓度在10-200μmol/L之间时己烷相中的碳量子点有明显的线性关系。
[Abstract]:Carbon quantum dots (QDs) are nontoxic and highly fluorescent nanomaterials, which have been widely used in biomedicine, photoelectric sensor and photocatalyst due to their advantages of simple preparation, good water solubility and easy functionalization. In this paper, carbon quantum dots with high fluorescence intensity and good stability were prepared by conventional microwave reactor and single-mode microwave reactor using L-cystine as raw material. The effects of various factors on the fluorescence properties of carbon quantum dots were studied and used as a fluorescent material for dyeing cotton fibers, doping silicone rubber, making invisible fluorescent ink and detecting metal ions. The main conclusions are as follows: (1) the fluorescent carbon quantum dots prepared by single-mode microwave reactor have good dispersion in aqueous solution, near spherical appearance, uneven particle size and average size of 2-6 nm. The aqueous solution of carbon quantum dots is yellowish in fluorescent light and green fluorescence in 365 nm UV lamp. The optimum fluorescence excitation wavelength is 420 nm, the maximum fluorescence emission wavelength is 505 nm, and the fluorescence quantum yield is 24 nm. The carbon quantum dots extracted into organic phase are colorless under fluorescent lamp, blue fluorescence is emitted by ultraviolet lamp, the optimum fluorescence excitation wavelength is 365 nm, the maximum fluorescence emission wavelength is 430 nm, and the average fluorescence quantum yield in chloroform and dichloromethane is 86 cm. No matter in water or organic phase, the position of maximum emission wavelength does not change with the change of excitation wavelength. The carbon point in water phase can be stored in 4 OC refrigerator for a long time, and the carbon point in organic phase can be stored for a long time at room temperature. With the increase of reaction time and the concentration of sodium hydroxide, the fluorescence intensity of the carbon quantum dots increased first and then decreased. The optimum reaction temperature is 135-140 掳C and the concentration of sodium hydroxide in the reaction system is 0.7-0.9 mol / L. Water phase carbon quantum dots have fluorescence properties in a wide range of pH, and the fluorescence intensity weakens with the increase of pH.) in the experiment, carbon quantum dots can be used as fluorescent materials to dye cotton, and can also be doped with silicone rubber. And can make fluorescent ink. It was found that the fluorescence of cotton fibers dyed with carbon quantum dots in aqueous phase was not firm enough, and that in chloroform phase, the fluorescence of cotton fibers dyed by carbon quantum dots in chloroform phase was more firm, and that silicone rubber doped with carbon quantum dots in water phase was yellowish and opaque. The ultraviolet lamp shows strong blue-green fluorescence, using organic carbon quantum dot doped silicone rubber colorless and transparent, and emitting blue fluorescence under the ultraviolet lamp. Fluorescent ink, prepared using carbon quantum dots, can be used for writing and inkjet printing, which is shown without writing in a fluorescent lamp. However, by studying the quenching effect of a variety of metal cations and some anions on the fluorescence carbon quantum dots, it is found that a few ions have little effect on the fluorescence intensity of the carbon quantum dots. The carbon quantum dots in hexane phase have a strong response to Fe~(3 and Fe _ 2O _ 2 Cu _ 2. The fluorescence quenching response of carbon quantum dots in water and organic phase to Fe~(3) is rapid. When the concentration of Fe~(3) is 100 渭 mol/L, the fluorescence quenching of carbon quantum dots in water phase shows a linear relationship, and when the concentration of Fe~(3) is between 10-200 渭 mol/L and 10-200 渭 mol/L, there is an obvious linear relationship for the carbon quantum dots in hexane phase.
【学位授予单位】：青岛科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O657.3

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