金纳米粒子调控量子点超辐射研究

发布时间：2018-10-16 10:46

【摘要】：量子点作为生物检测中新兴起来的一种荧光标记物,它与传统的半导体体材料相比出现了一些特殊的光电特性,因此在生物标记、检测、发光器件等多个研究领域具有较大的发展前景。由于表面光电信号的增强效应与低毒副作用,金纳米粒子被普遍应用在医学、生物检测等领域中。在合适的条件下,贵金属纳米结构表面的等离子体共振效应能够有效地增强量子点的辐射衰减率,目前通过这种方法来提量子点生物检测体系的灵敏度成为研究热点。本论文建立了金纳米结构增强量子点超辐射效应的理论模型,并在实验上进行了研究。以溶剂热合成法制备了有机物包裹的量子点团簇为研究对象,利用扫描近场光学显微镜来研究量子点团簇的超辐射效应,并探索金纳米粒子调控量子点集合的超辐射效应的方法,从而达到增强荧光的效果。论文的主要工作包括两个方面:1.量子点的超辐射效应。在理论上,推导了以Wannier激子为辐射模型的Dicke超辐射公式,从而获得量子点团簇半径与其辐射衰减率的立方关系;在实验上,以扫描近场光学显微镜为实验平台,将孔径针尖精确地定位到大小不同的单个量子点团簇上,并进行激发测量光谱。实验结果表明:当量子点胶体团簇半径小于55nm时,超辐射效应随团簇半径的增大而呈立方函数趋势增强,与理论相符;当半径大于55nm时,超辐射效应随团簇半径的增大而偏离理论曲线。2.金纳米结构调控量子点的超辐射。用辐射衰减率模型来描述金纳米结构对量子点的超辐射效应的影响,通过控制聚电解质双分子层的厚度来调控金纳米粒子薄膜与量子点集合之间的距离。实验结果表明聚电解质双分子层达到6层时,即间距在14nm左右,量子点集合的荧光强度最大,强度比量子点集合自身的强度增强了1.4倍。从实验中获得有效增加量子点辐射衰减率的方法,增强量子点荧光,从而满足生物检测中高灵敏度的需要。
[Abstract]:As a new fluorescent marker in biological detection, quantum dots have some special photoelectric properties compared with traditional semiconductor materials. Luminescent devices and other research fields have a great development prospects. Gold nanoparticles have been widely used in medicine, biological detection and other fields due to the enhancement of surface photoelectric signals and low toxicity and side effects. The plasmon resonance effect on the surface of noble metal nanostructures can effectively enhance the radiation attenuation rate of quantum dots under suitable conditions. In this paper, a theoretical model of gold nanostructures to enhance the superradiance effect of quantum dots is established and studied experimentally. The solvothermal synthesis method was used to prepare organic coated quantum dot clusters. Scanning near-field optical microscopy was used to study the superradiance effect of quantum dots clusters. The method of controlling the superradiance effect of quantum dot set by gold nanoparticles is explored, so that the fluorescence enhancement can be achieved. The main work of this paper includes two aspects: 1. Superradiance effect of quantum dots. In theory, the Dicke superradiance formula with Wannier exciton as radiation model is derived, and the cubic relation between the radius of quantum dots and its radiation attenuation rate is obtained, and the scanning near-field optical microscope is used as the experimental platform. The aperture tip is accurately located on a single quantum dot cluster of different sizes and the excitation spectra are measured. The experimental results show that when the radius of quantum dot colloid cluster is less than 55nm, the superradiance effect increases with the increase of cluster radius, which is consistent with the theory, and when the radius is larger than 55nm, The superradiation effect deviates from the theoretical curve with the increase of cluster radius. 2. Gold nanostructures regulate the superradiation of quantum dots. The radiation attenuation rate model is used to describe the superradiance effect of gold nanostructures on quantum dots. The distance between gold nanoparticles film and quantum dot set is controlled by controlling the thickness of polyelectrolyte bimolecular layer. The experimental results show that when the polyelectrolyte bimolecular layer reaches 6 layers, that is, the spacing is about 14nm, the fluorescence intensity of the quantum dot set is the largest, and the intensity of the quantum dot set is 1.4 times higher than that of the quantum dot set itself. An effective method to increase the radiation attenuation rate of quantum dots and enhance the fluorescence of quantum dots is obtained from the experiments, which meets the need of high sensitivity in biological detection.
【学位授予单位】：贵州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB383.1;O614.123

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