金纳米颗粒的可控制备及其光学性能研究

发布时间：2018-02-07 09:03

  本文关键词： 局域表面等离激元 表面增强拉曼散射 金纳米棒 金纳米双锥 Au@Cu_2O异质结复合结构　出处：《湖北工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：金纳米颗粒表现出很强的表面等离子体共振效应(Localized surface plasmon resonance,LSPR),其吸收峰的位置与纳米颗粒的几何形状,核壳结构,大小以及周围介质有关。虽然LSPR能够监测到吸附在金纳米颗粒表面的分析物分子,但是消光光谱并不能够识别吸附分子结构的整体特征,而振动光谱却可以弥补这一不足。表面增强拉曼光谱(Surface-enhanced Raman spectroscopy,SERS)能够显示出分子的特征振动图谱且不会损坏分析物的结构。通过将LSPR与SERS两种技术联用,可以获取分析物的定量和定性信息。非球形金纳米颗粒通过改变其尺寸和形状能实现可见和红外波段的连续可调谐,并与不同激发波长的检测目标相匹配等优势而受到广泛关注。在本论文中,我们设计与合成了不同结构的金纳米颗粒,探索了金纳米颗粒在分子检测方面的应用;另外制备了Au@Cu_2O异质结复合结构,并利用该结构在光催化降解方面进行了研究。主要内容如下:1.金纳米颗粒的调控及其在SERS中的应用研究(1)采用水相合成法制备了一系列不同长径比的金纳米棒结构,金纳米棒的长径比主要通过硝酸银和种子溶液的含量来调节,并且通过调节长径比可精确调控其对应的LSPR峰。实验分别以不同LSPR的金纳米棒为基底,采用LSPR与SERS联用技术来测定拉曼分子,并分析了LSPR与SERS之间的关联效应;实验和理论结果表明金纳米棒对于拉曼分子的测定具有较高的灵敏度,当LSPR与拉曼激发波长相匹配时,增强效果可以达到10-7 mol/L。(2)采用金纳米棒作为种子溶液,有效实现金纳米颗粒从棒状到截角八面体再到八面体的系统性形状演化。此种横向生长模式为金纳米棒调整消光截面和纵向等离子体波长提供了可选择方式,这将促进其作为新材料在生物技术、光电子学和光学等领域的应用。(3)制备了均匀性较高的金纳米双锥结构,并以此为基础合成了金核银壳纳米棒结构,分别以它们为基底探究了两种结构对SERS的增强效应。实验和理论结果表明金纳米双锥具有一个五边形基底和两个尖锐的顶点,产生了新的额外“热点”。因此,与金纳米棒相比,金纳米双锥对周围的折射率更加灵敏,局域电场增强效应更强。该材料可以应用于生物活体内,对今后癌细胞的检测有着巨大的潜力。2.Au@Cu_2O异质结复合结构的制备及其在光催化降解中的应用研究实验制备了Au@Cu_2O异质结复合结构,探究了Cu_2O立方体生长的机理以及表面活性剂的必要性,并讨论了外层Cu_2O对内部金纳米棒吸收谱的影响。最后,将Cu_2O立方体结构和Au@Cu_2O复合结构用于降解罗丹明B研究,实验结果表明Au@Cu_2O异质结复合结构光降解能力要强于Cu_2O立方体结构。本论文较系统地研究了金纳米颗粒结构中的表面等离激元激发引发的局域电场增强效应与微结构之间的关系,进而通过设计金纳米结构的几何参数来调节表面等离激元共振,实现高SERS效应并能满足特定应用需求金纳米颗粒的可控制备,为进一步开发金纳米颗粒的应用提供了理论和实验基础。
[Abstract]:Gold nanoparticles exhibit strong surface plasmon resonance effect (Localized surface plasmon resonance, LSPR), the position of the absorption peak and nano particle geometry, core-shell structure, size and the surrounding medium. Although LSPR can detect the analyte molecules adsorbed on the surface of gold nanoparticles, but not to the overall extinction spectrum feature recognition of adsorption of molecular structure, and vibrational spectra can compensate for this deficiency. The surface enhanced Raman spectrum (Surface-enhanced Raman, spectroscopy, SERS) can show the characteristics of molecular vibration and will not damage the structure of analytes. By LSPR and SERS two kinds of technique, can obtain the quantitative and qualitative information analysis non spherical gold nanoparticles with tunable change its size and shape to achieve the visible and infrared wavelengths, and with different excitation wavelength. The target of matching advantage and attracted widespread attention. In this thesis, we designed and synthesized gold nanoparticles of different structure, explores the application of gold nanoparticles in molecular detection; in addition to preparation of Au@Cu_2O heterojunction composite structure, and carried out the research on photocatalytic degradation by the structure. The main contents are as follows: 1. Study on the regulation of gold nanoparticles and its application in SERS (1) using the aqueous preparation of a series of different aspect ratio of gold nanorods structure, the aspect ratio of gold nanorods to adjust the main content by silver nitrate and seed solution, and by adjusting the aspect ratio adjust the corresponding LSPR peak. The experiment with different LSPR gold nanorods as the base, combined with technology to measure the Raman molecular by LSPR and SERS, and analyzes the correlation effect between LSPR and SERS; the theoretical and experimental results show that the Gold nanorods have high sensitivity for the determination of Raman molecules, when LSPR and Raman excitation wavelength, enhancement effect can reach 10-7 mol/L. (2) using gold nanorods as seed solution, the effective realization of system of shape of gold nanoparticles from rod to truncated eight surface to the eight surface body evolution provides. The choice of the lateral growth mode for the adjustment of gold nanorods extinction cross section and longitudinal plasma wavelength, which will promote it as a new material in bio technology, optoelectronics and optical applications. (3) high uniformity of gold bipyramids structure were prepared, and the Au core Ag shell nanorods were synthesized based on structure in their basement, respectively explores the enhancement effect of two kinds of structure of SERS. The experimental and theoretical results show that the nano gold double cone has a Pentagon base and two sharp vertices, the Additional "hot" new. Therefore, compared with the gold nanorods, gold bipyramids to the surrounding refractive index is more sensitive, local field enhancement effect is stronger. The material can be applied to in vivo detection of cancer cells in the future, has a huge potential of.2.Au@Cu_2O heterojunction composite structure preparation and light study on the application of photocatalytic degradation experimental preparation of Au@Cu_2O heterojunction composite structure, to explore the mechanism of Cu_2O cube growth and necessity of surfactant, and discusses the influence of Cu_2O on the absorption spectrum of the outer layer inside the gold nanorods. Finally, the Cu_2O cube structure and Au@Cu_2O composite structure for the degradation of rhodamine B, the experimental results show that Au@Cu_2O heterojunction composite structure stronger photocatalytic ability in Cu_2O cubic structure. This paper systematically studies the structure of gold nanoparticles in the surface plasmon excitation induced by The relationship between the effect and the micro structure of the local electric field enhancement, and then through the design of geometric parameters of gold nanostructures to regulate surface plasmon resonance, high SERS effect and can meet the requirements of a specific application controlled synthesis of gold nanoparticles, provides theoretical and experimental basis for further development and application of gold nanoparticles.

【学位授予单位】：湖北工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ131.23;TB383.1
，

本文编号：1494009