掺杂碳量子点的合成及其性质研究

发布时间：2018-03-17 13:20

  本文选题：掺杂碳量子点　切入点：微波合成　出处：《南京大学》2017年硕士论文　论文类型：学位论文

【摘要】：碳量子点(CQDs)是新型碳纳米材料,荧光强度高且稳定,对生物体和环境无害。碳量子点可以与无机物或有机物复合,在生物探针和催化等方面有着广泛应用前景,近年来已经成为研究热点。目前的研究主要是对碳量子点进行非金属元素掺杂,改变其电子结构和光学性质,但通常直接焙烧或水热合成法存在合成温度高,时间长以及掺杂量低等问题。鉴于此,我们发展了高效微波辅助热合成法,基于"自下而上"合成路径一步合成了兼具高荧光发光性能和催化活性的碳量子点。本论文研究包括两部分:第一部分工作,研制了高含量掺杂氮硫的碳量子点(N,S-CQDs),探讨了氮硫掺杂碳量子点的合成机理、荧光发光特性及类酶催化活性。第二部分工作采用甲基咪唑摀四氟硼酸盐离子液和碳源前驱体研制了硼、氮和氟三元掺杂碳量子点(B,N,F-CQDs),研究了前驱体比例和反应时间对硼、氮和氟掺杂碳量子点荧光性能的影响,获得了具有高荧光量子效率的碳量子点。主要研究成果如下:Ⅰ.N,S-CQDs的合成及类酶催化活性的研究以柠檬酸为碳源、硫脲为氮源和硫源,通过微波固相热合成方法在50秒内合成具有高氮和硫掺杂水平的氮、硫共掺碳量子点N,S-CQDs。研究掺杂碳量子点合成机理,发现硫脲作为弱碱可以加快反应速率,降低碳化温度,减少反应损失,从而提高了掺杂水平。对掺杂碳量子的光学性质和类酶催化活性的研究发现相对于未掺杂的CQDs,N,S-CQDs具有更高的荧光量子效率和类酶催化活性;XPS研究发现进入共轭骨架的吡啶结构N是主要掺杂类型,是类酶催化活性的中心,在边缘的吡咯结构N是作为荧光发射中心,从而实现了样品同时具有高的酶模拟催化活性和光致发光量子产率。Ⅱ.三元掺杂CQDs的合成采用离子液体1-丁基-3-甲基咪唑摀四氟硼酸盐([BMIm][BF4])和柠檬酸为碳源,一步合成了 F掺杂CQDs。获得直径范围在4nm至5nm的粒径均一的三元掺杂碳量子点B,N,F-CQDs,其最高荧光光量子产率为41.8%;对各掺杂元素的浓度和结构的分析发现,同时存在C-F半离子键和C-F共价键,推测氟作为荧光发射中心对材料的发光性能起到关键作用。
[Abstract]:Carbon quantum dots (CQDs) are novel carbon nanomaterials with high fluorescence intensity and stability, which are not harmful to organism and environment. Carbon quantum dots can be combined with inorganic or organic compounds, and have wide application prospects in biological probe and catalysis. In recent years, it has become a research hotspot. The current research is mainly about doping carbon quantum dots with non-metallic elements to change their electronic structure and optical properties, but the synthesis temperature is usually high in direct calcination or hydrothermal synthesis. In view of this, we have developed a high efficiency microwave assisted thermal synthesis method. Based on the "bottom-up" synthesis path, carbon quantum dots (QDs) with high luminescence and catalytic activity were synthesized in one step. Carbon quantum dots with high content of nitrogen and sulfur were prepared. The synthesis mechanism of carbon quantum dots doped with nitrogen and sulfur was discussed. In the second part, boron, nitrogen and fluorine ternary doped carbon quantum dots were prepared by using methyl imidazolium tetrafluoroborate ionomer and carbon source precursor. The effects of precursor ratio and reaction time on boron were studied. Carbon quantum dots with high fluorescence efficiency were obtained by the influence of nitrogen and fluorine-doped carbon quantum dots. The main results are as follows: 鈪，

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