复合材料图纹结构中“热点”构建及表面增强拉曼效应研究

发布时间：2018-07-27 12:10

【摘要】：表面增强拉曼散射(Surface-enhanced Raman Scattering,SERS)作为一种高灵敏度检测手段,基底制备是关键环节,活性强、稳定性好、可重复使用的基底对于应用和基础研究都具有重要意义。本文主要将胶体球有序模板和磁控溅射技术相结合,制备(SiO2-Ag)复合型纳米图纹结构阵列,构筑有序度好、稳定性高的SERS活性基底体系,使之适用于高灵敏度SERS效应的应用检测。研究基底构型、颗粒尺寸、缝隙密度、表面形态等因素对基底表面电磁场分布和等离子体耦合的调制作用,探索SERS效应的物理增强机制。首先,利用磁控溅射系统制备Si O2-Ag平面复合型SERS基底,SiO2-Ag复合基底比单纯Ag膜的表面粗糙度更大。通过共溅射的方法改变材料的构型实现对SERS基底表面粗糙度的调控,从而实现了对SERS活性基底的“热点”密度及其增强性能的控制。其次,以不同直径的聚苯乙烯胶体球阵列为衬底,利用双靶共溅射Ag和SiO2的方法制备网状“杨梅”型结构阵列。每个“杨梅”是由无定形的SiO2包裹的Ag纳米粒子所构成的,Ag纳米粒子大小为10-20 nm,SiO2厚度为2-5 nm,这种结构基底提供了更多的“热点”。SiO2-Ag纳米帽子呈现各向异性生长的特点,纵向生长速度大于横向生长速度。随着SiO2-Ag薄膜厚度的增加,薄膜的表面粗糙度以及相邻“杨梅”之间的距离都随之变化,改变了相邻局域电磁场的耦合,从而实现对SERS增强能力的调控。不同激发光波长对样品测试SERS的实验结果表明:“杨梅”型SiO2-Ag纳米结构阵列在可见到近红外光激发下均表现出较高的增强能力,且整个样品表面具有较好的稳定性和均匀性。最后,利用胶体球模板和物理沉积技术相结合,制备了[Ag 30 nm/SiO2 5 nm]n(n=1-4)多层膜纳米结构阵列,SEM形貌测试显示多层膜阵列沿纵向生长,形成纳米“柱-帽”对结构,并且具有良好的SERS增强性能。热处理结果表明,[Ag/SiO2]n(n=4)多层膜阵列随着热处理温度的升高表面形貌发生巨大的变化;其中热处理600度后的样品SERS增强最大。SERS光谱测试表明,热处理600度后,随着周期数的增加,拉曼峰得到明显的增强。SiO2层不仅可以对拉曼具有较好的增强效果,并且提高了SERS基底的稳定性。
[Abstract]:Surface enhanced Raman scattering (Surface-enhanced Raman scattering) is a high sensitivity detection method. Substrate preparation is a key link with strong activity and good stability. The reusable substrate is of great significance for application and basic research. In this paper, the colloidal sphere ordered template was combined with magnetron sputtering technique to fabricate (SiO2-Ag) composite nanogram structure array to construct a SERS active substrate system with good order and high stability, which makes it suitable for the application of high sensitivity SERS effect detection. The modulation effects of substrate configuration, particle size, gap density and surface morphology on the electromagnetic field distribution and plasma coupling on the substrate surface are studied, and the physical enhancement mechanism of the SERS effect is explored. Firstly, the surface roughness of Si O2-Ag planar composite SERS substrate SiO2-Ag is higher than that of pure Ag film by magnetron sputtering system. The surface roughness of SERS substrate can be controlled by changing the configuration of the material by co-sputtering, thus controlling the "hot spot" density of SERS active substrate and its enhancement performance. Secondly, using polystyrene colloidal sphere arrays with different diameters as substrates, reticulated "bayberry" arrays were prepared by co-sputtering Ag and SiO2 with double targets. Each "Myrica" is composed of amorphous Ag nanoparticles wrapped in SiO2. The size of Ag nanoparticles is 10-20 nm / Sio _ 2 and the thickness of Sio _ 2 is 2-5 nm. This structure substrate provides more "hot spots". SiO2-Ag nanometers exhibit anisotropic growth characteristics. The longitudinal growth rate is higher than the transverse growth rate. With the increase of the thickness of SiO2-Ag films, the surface roughness of the films and the distance between the adjacent "Myrica rubra" changes, which changes the coupling of adjacent local electromagnetic fields and realizes the regulation of the enhancement ability of SERS. The experimental results of SERS measurements with different excitation wavelengths show that the "Myrica rubra" type SiO2-Ag nanostructure array exhibits high enhancement ability under near-infrared light excitation, and the whole surface of the sample has good stability and uniformity. Finally, the [Ag 30 nm/SiO2 5 nm] n (ng 1-4) multilayer nanostructure array was prepared by using the colloid sphere template and physical deposition technique. The results showed that the multilayer film array grew along the longitudinal direction and formed a "column-cap" pair of nanocrystalline films. And has the good SERS enhancement performance. The results of heat treatment show that the surface morphology of [Ag/SiO2] n (nni4) multilayer array changes greatly with the increase of heat treatment temperature, and the maximum SERS enhancement of the sample after heat treatment of 600C shows that the number of cycles increases with the heat treatment of 600C. The Raman peak can not only enhance the Raman spectra, but also improve the stability of SERS substrate.
【学位授予单位】：吉林师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB33

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