高效碳纳米点的制备及其生物与激光应用的研究

发布时间：2018-03-26 20:40

本文选题：碳纳米点　切入点：荧光量子效率　出处：《中国科学院长春光学精密机械与物理研究所》2017年博士论文

【摘要】：纳米发光材料具有良好和独特的发光性能,经过多年的广泛研究和快速发展,新型高性能的纳米发光材料不断涌现,在信息光电子和生物医学领域显示了重要的应用前景。在纳米材料中,碳基纳米材料包括碳纳米管、石墨烯和富勒烯的研究是纳米科技的前沿领域,一直备受世人瞩目。近年来,人们又发现了一种发光性能出色的球状颗粒的新型碳纳米材料,称为碳纳米点。和传统的金属、半导体量子点相比,碳纳米点具有合成工艺简单、成本低廉、水溶性和生物相容性好、毒性低、荧光性能优良并且稳定性好等优点,在光催化、传感器、激光器、LED、光伏器件、生物成像和光电探测器等领域展现了良好的应用前景。1、本文针对以往碳纳米点荧光效率偏低的问题,提出了一种较好的解决思路。即通过一步微波合成方法使柠檬酸与含氨基的羟基化合物进行脱水缩合和碳化反应,获得了具有氮掺杂和表面羟基官能化修饰的碳纳米点,该种碳纳米点的荧光效率可高达99%,通过系列碳点材料的表征,证明了石墨氮掺杂和表面富羟基修饰是实现高荧光效率的原因。2、本文针对以往碳纳米点易聚集猝灭的现象,通过一步微波合成方法研制出具有抗自聚集猝灭的固态荧光碳纳米点,该碳纳米点无任何支撑体系,荧光量子效率可达40%,而且能在1 min之内对14种最具代表性的细菌实现超快速染色,其染色效果优于常用的商业化荧光染料。3、本文针对以往碳纳米点易聚集猝灭的现象,合成一种对浓度有依赖特性的可以从聚集猝灭向聚集发射转变的碳纳米点。经过材料的初步表征发现,聚集体黄光发射的增强现象,很可能是由于单分散的碳纳米点与碳纳米点聚集体之间发生了F?rster能量转移而引起的。4、首次发现具有激发波长独立特性的碳纳米点在光泵浦下比其他碳纳米点更容易实现低阈值的放大自发辐射。通过傅里叶变换红外光谱和X射线光电子能谱研究手段分析,发现具有激发波长独立特性的碳纳米点的含氧基团C-O-C/C-O-H很少,使得n-π*带隙内与C-O-C/C-O-H相关的激发态较少,在π*→n跃迁中,粒子数容易反转。此外还发现具有激发-发射独立性的碳纳米点的辐射跃迁速率和受激发射截面显著高于具有激发-发射依赖性的碳纳米点。我们还首次实现了平面波导结构的全固态碳纳米点薄膜的光泵浦放大自发辐射。
[Abstract]:Nano-luminescent materials have good and unique luminescent properties. After years of extensive research and rapid development, new high-performance nano-luminescent materials have been emerging. In the field of information optoelectronics and biomedicine, the research of carbon based nanomaterials, including carbon nanotubes, graphene and fullerene, is the frontier of nanotechnology. In recent years, a new kind of carbon nanocrystalline material, called carbon nanocrystalline, has been discovered. Compared with traditional metal and semiconductor quantum dots, carbon nanocrystals have a simple synthesis process. Low cost, good water solubility and biocompatibility, low toxicity, excellent fluorescence performance and good stability, etc., in photocatalysis, sensors, lasers, LED, photovoltaic devices, etc. Biological imaging and photodetectors have shown good application prospects. In this paper, the low fluorescence efficiency of carbon nanowires has been studied. A better way to solve the problem was put forward, that is, by one-step microwave synthesis, citric acid was dehydrated, condensed and carbonized with amino group, and the carbon nanowires with nitrogen-doped and surface hydroxyl functionalized modification were obtained. The fluorescence efficiency of this kind of carbon nanowires can be as high as 99%. Through the characterization of a series of carbon point materials, it is proved that graphite nitrogen doping and surface hydroxyl rich modification are the reasons for achieving high fluorescence efficiency. In this paper, the phenomenon of agglomeration and quenching of carbon nanowires is discussed. A solid-state fluorescent carbon nanopoint with anti-self-agglomeration quenching was prepared by one-step microwave synthesis method, which has no support system. The fluorescence quantum efficiency can reach 40%, and it can achieve super fast dyeing of 14 most representative bacteria within 1 min, which is superior to commercial fluorescent dye. 3. This paper aims at the phenomenon that carbon nanoparticles are easy to gather and quench. A concentration-dependent carbon nanodot was synthesized, which can change from agglomeration quenching to aggregate emission. The enhancement of yellow light emission of aggregates was found by the preliminary characterization of the material. Probably due to the F- between the monodisperse carbon nanoparticles and the carbon nanoparticles aggregates? Rster energy transfer is the first time to find that carbon nanowires with independent excitation wavelength are easier to achieve low threshold amplified spontaneous emission than other carbon nanocrystals under optical pumping. Fourier transform infrared spectroscopy (FTIR) and X. Analysis of X-ray photoelectron spectroscopy, It was found that there were few oxygen-containing C-O-C/C-O-H groups in carbon nanowires with independent excitation wavelength, which resulted in fewer excited states associated with C-O-C/C-O-H in the n- 蟺 * band gap and in 蟺 *. 鈫扤 transition, It is also found that the radiative transition rate and the stimulated emission cross section of the carbon nanowires with excitation and emission independence are significantly higher than those of the carbon nanowires with excitation emission dependence. We have also realized for the first time. Optical pumping and amplifying spontaneous emission of all solid carbon nanodot films with planar waveguide structure.
【学位授予单位】：中国科学院长春光学精密机械与物理研究所
【学位级别】：博士
【学位授予年份】：2017
【分类号】：O613.71;TB383.1

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