毛细管中二氧化钛有序微纳结构SERS基底制备

发布时间：2018-11-20 10:22

【摘要】：表面增强拉曼散射(Surface-enhanced Raman Scattering,SERS)以高灵敏度、样品前处理简单、操作简便等诸多优点而受到广泛关注,并且在近几年的科学研究中发展迅速。通过SERS可以获得待测物的增强拉曼光谱,从而解析其分子结构信息,因此SERS在生化检验、考古与艺术品鉴定、生物医学、食品安全等领域中具有巨大应用潜力。表面增强拉曼散射基底的制备是SERS研究的重点问题。现在常用的SERS基底大多为金、银、铜等贵金属制备而成的金属纳米阵列,这是因为金属纳米材料表面等离激元共振带来的电磁场增强起到了拉曼增强的效果,但是金属纳米阵列制备过程相当复杂,且其造价昂贵,另外金属的等离激元共振损耗较大,这就使得等离激元SERS基底的应用受到了一定的限制。近年来,一种基于无表面等离激元(plasmon-free)半导体材料二氧化钛有序微纳结构的SERS基底逐渐兴起,二氧化钛可以利用自身的电子转移的特性来替代表面等离激元共振,并且有序的二氧化钛微纳结构可以使得激光在二氧化钛有序微纳结构中形成多重散射,增加了光与待测分子的作用时间,从而也可以有效地增强拉曼光谱,展现了很好的研究价值与应用前景。基于此,本论文通过简单且经济的方法制备出三维的二氧化钛有序微纳结构,探索了其SERS检测性能。具体开展的工作如下:(1)使用模板法在毛细管内制备了二氧化去钛反蛋白石有序微纳结构。通过将小粒径二氧化钛纳米粒子填充到聚苯乙烯模板缝隙中,在毛细管内组装了三种不同结构色(反射峰分别为430 nm,551 nm,667 nm)的完整、均一、高质量的基底。(2)使用原子层沉积的方法制备了一种二氧化钛/二氧化硅壳-核有序微纳结构毛细管。首先在毛细管内组装二氧化硅正结构,然后通过原子层沉积在二氧化硅表面镀上一层厚度可控的二氧化钛薄膜,并对不同厚度二氧化钛的样本进行了反射峰位移和表面形貌结构变化的分析,随着镀膜厚度的增加,有序微纳结构表面的缝隙逐渐被填充,反射峰发生红移,反射峰的数值呈线性增长。(3)天然有序微纳结构蝴蝶翅膀因其可以对光进行调制的优良特性也可以用作SERS基底的模板,所以为了系统研究二氧化钛有序微纳结构基底的拉曼增强效果,我们用模板法和原子层沉积两种方法制备出不同的二氧化钛的蝶翅结构复制品,并且与之前同样方法制备的两种基于人工模板的二氧化钛有序微纳结构比较它们各自的拉曼增强效果。实验发现这几种基底均有拉曼增强效果。其中二氧化钛反结构的灵敏性最高,二氧化钛/二氧化硅壳-核结构次之,其次是原子层沉积法制备的二氧化钛蝶翅结构,最后是模板法制备的二氧化钛蝶翅结构,两种二氧化钛蝶翅结构均低于前者。与蝶翅结构这种平面基底相比,毛细管内基底的SERS灵敏度,并且使用方便,显示了较好的应用前景。
[Abstract]:Surface enhanced Raman scattering (Surface-enhanced Raman Scattering,SERS) has attracted much attention due to its high sensitivity, simple sample pretreatment and easy operation, and has been developed rapidly in recent years. The enhanced Raman spectra of the object to be tested can be obtained by SERS, and the information of its molecular structure can be analyzed. Therefore, SERS has great application potential in the fields of biochemical examination, archaeology and art identification, biomedicine, food safety and so on. The preparation of surface-enhanced Raman scattering substrates is an important issue in the study of SERS. Most of the current SERS substrates are metal nanoarrays made of precious metals such as gold, silver, copper, etc. This is because the enhancement of electromagnetic field caused by isoexciton resonance on the surface of metal nanomaterials has the effect of Raman enhancement. However, the fabrication process of metal nanoscale arrays is very complicated and expensive. In addition, the high resonance loss of metal isophosphors makes the application of SERS substrates limited to a certain extent. In recent years, a kind of SERS substrate based on the ordered micro and nano structure of titanium dioxide semiconductor material without surface isophosphorus (plasmon-free) has been gradually developed. Titanium dioxide can substitute for surface isoexciton resonance by using its own electron transfer characteristics. And the ordered TIO _ 2 structure can make the laser form multiple scattering in the ordered micro-nano structure of TIO _ 2, increase the time of interaction between the light and the molecule to be tested, so it can also effectively enhance the Raman spectrum. It shows good research value and application prospect. Based on this, the three-dimensional ordered micro-nano structure of titanium dioxide was prepared by a simple and economical method, and its SERS detection performance was explored. The main works are as follows: (1) the ordered nanostructures of detitanium dioxide reverse opal were prepared in capillary by template method. By filling the small particle size titanium dioxide nanoparticles into the polystyrene template slot, three different structure colors (the reflection peak is 430 nm,551 nm,667 nm) were assembled in the capillary tube. (2) A kind of TIO _ 2 / Sio _ 2 capillaries with ordered micro-nano structure was prepared by atomic layer deposition. First, the positive structure of silica was assembled in the capillary, and then a controllable thickness of titanium dioxide film was deposited on the surface of silica by atomic layer deposition. The change of reflection peak displacement and surface morphology of titanium dioxide samples with different thickness were analyzed. With the increase of coating thickness, the gap on the surface of ordered micro-nano structure was gradually filled, and the reflection peak was red-shifted. The value of the reflection peak increases linearly. (3) the natural ordered micro-nano structure butterfly wings can also be used as templates for SERS substrate because of their excellent properties of modulating light. So in order to study the Raman enhancement effect of titanium dioxide ordered micro-nano structure substrates, we prepared different replicas of titanium dioxide butterfly wings by template method and atomic layer deposition method. Their Raman enhancement effects were compared with two kinds of ordered TIO _ 2 microstructures based on artificial templates prepared by the same method. It is found that these substrates have Raman enhancement effect. Among them, titanium dioxide inverse structure is the most sensitive, titanium dioxide / silica shell-core structure is the second, the second is titanium dioxide butterfly wing structure prepared by atomic layer deposition, and the last is titanium dioxide butterfly wing structure prepared by template method. The structure of two titanium dioxide butterfly wings was lower than that of the former. Compared with the planar substrates, the SERS sensitivity of the capillary substrates is easy to use, which shows a good prospect of application.
【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O657.37

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