多种光色发射的荧光碳点制备及性能、应用研究

发布时间：2018-04-29 07:41

  本文选题：碳点 + 多种光色　； 参考：《上海师范大学》2017年硕士论文

【摘要】：荧光碳点与一些传统量子点和有机染料相比,具有一些独特的优势,如毒性低、水溶性好、光漂白性好、生物相容性好等,故受到越来越多的人关注,但一些碳点的制备方法复杂、荧光效率不高、长波荧光发射碳点尤其是红光甚至近红外光碳点少,因此,探究一种简的便方法制备高量子效率、多种光色发射的碳点很有必要。本文针对以上问题采用不同的制备方法制备了较高荧光效率的碳点,采用一步热解法制备高荧光效率的黄绿光碳点,又采用溶剂热法制备多光色发射的碳点。论文的主要研究内容和结果如下:1.以柠檬酸为碳源、尿素提供氮源一步热解法制备高荧光效率的黄绿光碳点。并对碳点的形貌、粒径、表面基团、发光性质等进行表征测试,发现碳点分布均匀,不团聚,粒径约为5 nm,表面含有大量亲水性有机基团,荧光量子效率高达78.3%;其激发峰为291 nm、360 nm、460 nm,发射主峰位于533 nm,调节激发波长365 nm~465 nm,其发射主峰保持不变,而在465 nm~525 nm,发射主峰红移;探究了制备黄绿光碳点最佳条件,得知最佳制备条件为原料柠檬酸与尿素摩尔比1:4、反应温度为200℃、反应时间为2 h;同时探究了碳点制备过程发生的变化,得知首先生成碳点前驱体,进一步反应得到碳点;研究了不同pH环境、不同有机溶剂、不同浓度无机盐离子环境、紫外光照射不同时间对碳点发光的影响,结果表明强酸、强碱环境对碳点荧光影响较大;极性较大溶剂中呈现黄绿光,且极性越大,发光越强,而在极性小的溶剂中大多呈现蓝光发射,甚至在极性极小的溶剂中不发光;其耐盐性及光漂白性极好;用其培养藻类,藻类生长良好证明碳点毒性低;将碳点用于打印、防伪、复合材料、光电材料,取得很好的效果。2.以柠嗪酸为共同碳源,采用一步溶剂热法制备了蓝、黄、红三种光色的碳点。三种碳点粒径均在5 nm以下,表面都有大量有机基团,蓝光碳点激发主峰为354 nm,此时发射主峰峰为458 nm,黄光碳点激发主峰为494 nm,发射主峰为562 nm,红光碳点激发主峰是621 nm,发射峰为655 nm,三种碳点的荧光量子效率都较高,蓝光为58.7%、黄光为34.5%、红光为23.8%。调节激发波长发现,蓝、红碳点发射波长对激发波长有一定的依耐性,而改变激发波长黄光碳点的发射峰保持不变。对三种碳点的耐盐性、光稳定性、毒性进行了测试,结果表明:三种碳点耐盐性好、光漂白性好、毒性低。将三种碳点用作荧光墨水、制备固态复合发光材料、LDE领域均收到不错的效果。
[Abstract]:Compared with some traditional quantum dots and organic dyes, fluorescent carbon dots have some unique advantages, such as low toxicity, good water solubility, good photobleaching, good biocompatibility and so on. However, the preparation methods of some carbon spots are complex, the fluorescence efficiency is not high, and the long wave fluorescence emission carbon points, especially the red light and even the near infrared carbon spots, are few. Therefore, it is necessary to explore a simple method to prepare carbon dots with high quantum efficiency and various photochromatic emission. In order to solve the above problems, the carbon spots with high fluorescence efficiency were prepared by different preparation methods, the yellowish green carbon spots with high fluorescence efficiency were prepared by one step pyrolysis, and the carbon spots with multiple photochromatic emission were prepared by solvothermal method. The main contents and results of this paper are as follows: 1. Using citric acid as carbon source, urea provides nitrogen source for one step pyrolysis to prepare yellowish-green carbon spots with high fluorescence efficiency. The morphology, particle size, surface group and luminescence properties of the carbon spots were characterized. It was found that the carbon spots were uniformly distributed and not agglomerated, and the particle size was about 5 nm, and there were a large number of hydrophilic organic groups on the surface. The fluorescence quantum efficiency is as high as 78.3 nm, the excitation peak is 291Nm ~ 360nm ~ (-1), the main emission peak is located at 533nm, and the excitation wavelength is nm~465 ~ (mm), and the main emission peak remains unchanged, while at 465 nm~525 nm, the main emission peak is red-shifted. The optimum conditions for preparing yellow-green carbon spots are investigated. The optimum preparation conditions are as follows: the molar ratio of citric acid to urea is 1: 4, the reaction temperature is 200 鈩，

本文编号：1819030