石墨烯、石墨烯纳米墙及其复合材料的SERS性能研究

发布时间：2018-01-10 03:14

本文关键词：石墨烯、石墨烯纳米墙及其复合材料的SERS性能研究　出处：《重庆理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：拉曼光谱是一种能够提供分子结构信息的强大技术,在拉曼光谱技术中表面增强拉曼光谱(SERS)以其超高的灵敏度(可到108)被物理、化学、生物等科学领域所广泛关注。对于SERS,其增强机理主要是物理增强(EM)和化学增强(CM)两种,物理增强是由于表面等离子体共振引起的电磁场增强,而化学增强是由于材料与分子之间的电荷转移引起的。很多贵金属都具有优异的物理、化学性能和较强的SERS效果,在众多贵金属中Ag的增强效果最为突出。然而,由于金属的吸附性差和不稳定性,导致金属SERS衬底不能广泛使用,因此寻找一种具有吸附性强,稳定性高且具有SERS活性的衬底材料是至关重要的。石墨烯是一种基于SP2杂化组成的单层碳原子构成的具有六角型呈蜂巢晶格的二维晶体,石墨烯以其优异的光学、电学和机械特性被广泛的用于显示、能源、探测、光电子等领域。在众多应用中,石墨烯还可以被应用于制备SERS衬底方面,其独特的结构使其具有较好的吸附性,因此石墨烯的稳定性又可以作为隔离SERS衬底和被测物的屏障,这是作为SERS衬底材料所梦寐以求的。目前,石墨烯金属SERS衬底的制备主要是把石墨烯转移到衬底上,此过程会发生石墨烯结构破坏、石墨烯与金属纳米粒子贴合不严等问题。而石墨烯纳米墙的出现使得石墨烯SERS衬底的研究进入一个新的高潮。石墨烯纳米墙可描述为自组装,垂直站立,几个多层石墨烯片纳米结构,其独特的三维结构可发展为SERS微结构衬底的一个新方向。一方面,三维立体式结构会使被测分子陷入墙结构中,使得SERS衬底具有更好的吸附性;另一方面,其三维结构具有可折叠、可拉伸、重量轻、不易碎、柔性好等特点,解决了传统SERS衬底在特殊条件下工作的难题。本论文采用在泡沫镍上原位生长石墨烯并引入银纳米粒子,通过衬底结构的观察其与理想结构的相似性,同时采用具有强烈荧光效应的罗丹明6G作为探针分子,对银纳米粒子修饰的石墨烯泡沫镍SERS衬底进行检测,并与镍薄片和泡沫镍以及石墨烯泡沫镍等SERS衬底进行增强效果对比,来验证银纳米粒子修饰的石墨烯泡沫镍SERS衬底的可行性。采用在铜箔衬底上直接原位生长石墨烯纳米墙,制备一种石墨烯纳米墙结构的SERS衬底(G-SERS)。以罗丹明6G作为探针分子,对石墨烯纳米墙SERS衬底进行拉曼增强效应的检测,并且通过不同生长时间的石墨烯纳米墙SERS衬底对R6G增强效果的对比,来验证石墨烯纳米墙结构SERS衬底的有效性。最后在确定最优生长时间的石墨烯纳米墙结构SERS衬底上镀银,来进一步增强SERS衬底的增强效应,且石墨烯纳米墙结构还起到增加衬底吸附性和稳定性的作用以及猝灭荧光和噪声的效果,在通过与银纳米粒子修饰的石墨烯泡沫镍SERS衬底的对比,证实银纳米粒子修饰的石墨烯纳米墙SERS衬底的增强效果最优异。
[Abstract]:Raman spectroscopy is a powerful technique that can provide molecular structure information. In Raman spectroscopy surface-enhanced Raman spectroscopy (SERS) is physically and chemically characterized by its ultra-high sensitivity (up to 108). For SERS, the enhancement mechanisms are mainly physical enhancement (EMV) and chemical enhancement (CMM). Physical enhancement is due to surface plasmon resonance electromagnetic field enhancement, while chemical enhancement is due to the charge transfer between materials and molecules. Many precious metals have excellent physics. The strengthening effect of Ag is the most prominent in many precious metals due to its chemical properties and strong SERS effect. However, due to the poor adsorption and instability of metals, metal SERS substrates are not widely used. Therefore, to find a strong absorbent. Graphene is a kind of two-dimensional crystal with hexagonal honeycomb lattice composed of monolayer carbon atoms based on SP2 hybrid. Graphene is widely used in display, energy, detection, optoelectronics and other fields for its excellent optical, electrical and mechanical properties. In many applications, graphene can also be used in the preparation of SERS substrate. Its unique structure makes it have better adsorption, so the stability of graphene can be used as a barrier to isolate the SERS substrate and the measured object, which is a dream material of SERS substrate. At present. The preparation of graphene metal SERS substrate is mainly to transfer graphene to the substrate, and the structure of graphene will be destroyed in this process. However, the appearance of graphene nanowires makes the study of graphene SERS substrates enter a new climax. Graphene nanowires can be described as self-assembly and vertical standing. The unique three-dimensional structure of several multilayer graphene nanostructures can be developed into a new direction of SERS microstructural substrates. On the one hand, three-dimensional three-dimensional structures will lead the molecules to fall into the wall structure. The SERS substrate has better adsorbability. On the other hand, its three-dimensional structure has the characteristics of folding, stretching, light weight, not easy to break, good flexibility and so on. The problem of traditional SERS substrate working under special conditions was solved. In this thesis, graphene was grown on nickel foam in situ and silver nanoparticles were introduced, and the similarity between the substrate structure and the ideal structure was observed. At the same time, the silver nanoparticles modified graphene foamed nickel (SERS) substrates were detected by using Rhodamine 6G as probe molecule with strong fluorescence effect. The results were compared with those of nickel thin sheet, foamed nickel and graphene nickel foam on SERS substrates. To verify the feasibility of silver nanoparticles modified graphene foamed nickel SERS substrates, graphene nanowires were grown directly on copper foil substrates in situ. A novel SERS substrate with graphene nanowall structure was prepared. Rhodamine 6G was used as probe molecule to detect the Raman enhancement effect of graphene nanowall SERS substrate. At the same time, the enhancement effect of SERS substrate on R6G was compared with that of graphene nanowall at different growth times. To verify the effectiveness of graphene nanowall structure SERS substrate. Finally, silver plating on the graphene nanowall structure SERS substrate with optimal growth time was carried out to further enhance the enhancement effect of SERS substrate. And the graphene nanowall structure can also increase the adsorption and stability of the substrate, as well as the effect of quenching fluorescence and noise, compared with the silver nanoparticles modified graphene foam nickel SERS substrate. It is confirmed that the silver nanoparticles modified graphene nanowall SERS substrate has the best enhancement effect.
【学位授予单位】：重庆理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ127.11;TB33

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