基于石墨烯及氧化石墨烯衬底的拉曼增强机理理论研究

The unique geometric and electronic structures of graphene and graphene oxide bring them the wonderful and ideal physical and chemical properties. Due to these fantastic properties, graphene and graphene oxide become the most potential materials in the entire world. They now are applied in surface chemistry, biotechnology, medical science and so on. Raman spectroscopy is a useful tool to detect the molecular geometry, but the intensity of Raman spectroscopy is very low. Therefore, Raman spectroscopy enhanced by the substrate is usually used technically to achieve more intense signal. Graphene and graphene oxide could be the substrate of surface enhanced Raman spectroscopy. The mechanism of enhancement of graphene and graphene oxide is chemical enhancement, which is different from the traditional metal substrates. However, the investigation of this mechanism of the enhancement is mainly performed experimentally. There are few theoretical studies about the mechanism of the enhancement of graphene and graphene oxide. In this project, we will theoretically study the surface enhanced Raman spectroscopy of Rhodamine molecules on graphene and graphene oxide by means of ab-initio method. The mechanism of the enhancement of graphene and graphene oxide will be revealed theoretically. The solvent influence on the surface enhanced Raman spectroscopy of graphene and graphene oxide will be investigated by means of explicit and implicit solvent models, as well as the relationship between the geometries and surface enhanced Raman spectroscopy.

石墨烯和氧化石墨烯独特的几何结构和电子结构决定了它们新奇的物理和化学性质。这些性质使得它们成为最具潜力和发展前途的应用材料之一。拉曼光谱是探测分子结构的指纹光谱，但其强度较低，在实验技术上通常需要利用衬底材料对拉曼光谱进行表面增强。石墨烯和氧化石墨烯可以作为表面增强拉曼光谱的衬底材料，对有机分子的拉曼光谱有较高效的增强作用。然而，目前对二者增强机理的研究主要停留在实验层面，理论方面的研究较少。本项目拟利用第一性原理，采用荧光染料罗丹明系列分子作为探测分子，研究石墨烯和氧化石墨烯作为衬底材料的表面增强拉曼光谱及其表面增强机理。在此基础上，为模拟实验中的溶液环境，确定探测分子在溶液中时吸附在石墨烯和氧化石墨烯表面的几何结构、电子结构与拉曼光谱之间的关系，本项目拟利用两种溶剂模型：显式溶剂模型和隐式溶剂模型来研究溶剂效应对表面增强拉曼光谱的影响。

石墨烯和氧化石墨烯独特的几何结构和电子结构决定了它们新奇的物理和化学性质。这些性质使得它们成为最具潜力和发展前途的应用材料之一。拉曼光谱是探测分子结构的指纹光谱，但其强度较低，在实验技术上通常需要利用衬底材料对拉曼光谱进行表面增强。石墨烯和氧化石墨烯可以作为表面增强拉曼光谱的衬底材料，对有机分子的拉曼光谱有较高效的增强作用。然而，目前对二者增强机理的研究主要停留在实验层面，理论方面的研究较少。本项目利用第一性原理，利用发展的准数值计算方法计算石墨烯表面的拉曼光谱。本项目的研究内容主要分为两部分：一、石墨烯的表面增强拉曼光谱及表面增强机理；二、氧化石墨烯的表面增强拉曼光谱及表面增强机理。我们主要以罗丹明系列分子分别与石墨烯及氧化石墨烯组成的分子团簇作为研究体系，利用密度泛函理论来计算该分子团簇的几何结构、电子结构、振动频率、振动模式、拉曼光谱及表面增强机理。同时，利用有效的实验技术对石墨烯及氧化石墨烯表面增强机理进行实验研究。本项目对研究石墨烯及氧化石墨烯作为衬底的表面增强拉曼光谱的理论研究及实验研究都有非常重要的意义。