具有表面增强拉曼活性的石墨烯/表面等离激元共振复合材料的制备与应用研究

Graphene is a two-dimensional material that is constructed as a single atomic sheet of conjugated sp2 carbon atoms. Since its discovery, graphene has attracted increasing interest because of its predominant electronic and mechanical properties and potential applications. Recently, scientists found that graphene and its derivations, such as graphene oxide (GO), could enhance the Raman signals of adsorbed molecules via chemical enhancement. Localized surface plasmon resonance (LSPR) materials, such as silver and gold nanoparticles, are common SERS substrates that can enhance the Raman signals of molecules via electromagnetic enhancement. In this project, the LSPR materials and graphene oxide are integrated to prepare graphene-LSPR nanocomposites, a new type of SERS substrates. In this way, the advantages of graphene and LSPR materials on SERS enhancement can be integrated, and the interactions between the chemical and electromagnetic enhancements can be displayed sufficiently as well. Grphene oxide with controllable size, layers, and reduction degrees will be produced. Its SERS activity and SERS enhancement mechanism will be investigated as well. By introducing wavelength self-limiting effect, self-assembly, and electrochemcial deposition, new strategies on the formation of graphene-LSPR nanocomposites can be developed. The influence of composite structure, constructing methods, and parameters of the LSPR matericals and graphene oxide on SERS activities of graphene-LSPR nanocomposites can be investigated. Thereby, the SERS activities of the substrate can be optimized. The SERS activities, stabilities, reproducibilities, and the scope of applications of the obtained nanocomposites will be evaluated. Based on the spectral activities of graphene/LSPR nanocomposite, a new type of multi-spectroscopic detection and sensing technique will be developed and studied. The development and further progress of this project is beneficial to promote the development of SERS technique, and lay a fundament on the application and popularization of SERS technique and the development of new-type nanocomposites.

本项目设想将LSPR材料与氧化石墨烯进行复合， 制备石墨烯/LSPR复合材料，将氧化石墨烯与LSPR材料在SERS增强方面的优势相结合，充分体现两种增强机制的相互作用，发展新型的SERS活性基底；探索影响氧化石墨烯材料SERS活性的关键因素，探讨其增强机制；引入波长自适应的原位光诱导、自组装、电化学沉积等方法，发展新的石墨烯与LSPR材料的复合途径；探讨复合结构与复合方式，材料中各参数对石墨烯/LSPR复合材料SERS活性的影响，并对其SERS活性进行优化；评价获得的复合材料的SERS活性、稳定性、重现性以及适用范围；建立并发展多元谱学检测与传感技术，拓展该复合材料在化学与生物传感等方面的潜在应用。本项目的开展与深入将有利于推动SERS技术的发展，为SERS技术应用与推广、石墨烯材料特性研究、发展新型复合材料等方面奠定基础，研究意义重大。

石墨烯不仅具有良好的电学、力学等性质，还具有独特的光谱活性，可有效猝灭被吸附分子的荧光信号，并通过化学增强方式获取分子的表面增强拉曼散射（SERS）信号。表面等离激元共振（LSPR）材料，例如金、银纳米粒子，是常规的SERS活性材料，主要通过物理增强方式放大拉曼信号。将石墨烯与LSPR材料结合起来，制备石墨烯/LSPR复合材料，可使石墨烯和LSPR材料在SERS增强方面的优势相结合，充分体现两种增强机理的相互作用，可发展新型的SERS活性基底，为SERS技术的应用与发展奠定基础。.本项目按计划进行了以下几个方面的研究：1）制备了具有不同尺寸、还原程度的氧化石墨烯，初步研究了氧化石墨烯的SERS活性与其还原程度之间的关系； 2）研究了银纳米粒子的可控制备方法，采用双波长光诱导、卤离子刻蚀和光诱导再生长结合等方法制备了LSPR可调控的银纳米结构；3）研究了银纳米粒子光诱导生长过程的诱导波长及反应温度的依赖性，通过控制诱导波长和反应温度可制备具有不同结构的银纳米粒子；4）研究了石墨烯与LSPR材料的复合方法；分别采用原位光诱导反应和自组装过程，将具有特定结构的金、银纳米粒子修饰到氧化石墨烯表面制备了石墨烯/LSPR复合材料；采用原位沉积法在银纳米结构表面直接沉积石墨烯制备石墨烯/LSPR复合结构；采用膜转移法将石墨烯薄膜覆盖在具有特定LSPR性质的银纳米粒子膜表面，并通过适当的退火处理，制备了具有特定LSPR性质的石墨烯/LSPR复合结构；结果表明这些复合材料具有较好的SERS活性。