平整基底上的拉曼信号增强技术及其应用

Surface enhanced Raman spectroscopy (SERS) is an attractive analytical technique which enables single-molecule sensitive detection and provides its chemical fingerprints. During the past decades, researchers have made great efforts towards an ideal SERS substrate. Based on their pioneering works, the original rough SERS substrates are replaced with more uniform metal nanostructure arrays prepared by various nano-tailoring or nano-assembly techniques. Yet molecules on these "uniform" SERS substrates are not real uniform on nanoscale. To further understand the SERS effect and fully excite its advanced applications, SERS substrate in a more "intelligent" form is still lacked. .The rising two-dimensional (2D) atomic crystals (such as graphene, boron nitride, MoS2, etc.) have attracted wide interests (especially for electronic applications). According to the perfect atomically flat characteristic of 2D (or quasi-2D) atomic crystals, we will exploit their potential applications in SERS. In this proposal, we first focus on the design, fabrication and applications of SERS technique with flat substrates. On one hand, the Raman enhancement effect (usually weak, 10~102) of pristine 2D atomic crystals and their chemical interactions with the probe molecules will be investigated. On the other hand, by introducing SERS-active metal nanostructures to an atomically flat 2D atomic crystal layer, we will exploit the applications of Raman enhancement (strong, can reach 108 or more) with localized electromagnetic "hot" spots on a flat surface. The purpose is to create a new SERS substrate with an atomically smooth surface for well-defined molecular interactions, yet also have the electromagnetic "hot" spots created by the metal nanostructures. For the later we will focus on the following four aspects: (1) Localized surface plasmon resonance on flat substrates-realization and characterization; (2) Novel analytical methods based on the SERS technique with flat substrates; (3) Study of chemical processes in SERS and plasmonic catalysis based on the SERS technique with flat substrates; (4) Flat SERS substrates in a transparent, freestanding and flexible form towards non-invasive and on-line analyses. We anticipate that our research results will take tremendous impact in both the theoretical understanding and practical applications of SERS.

拉曼光谱的应用范围遍及化学、物理学、生物学和医学等各个领域，但由于极低的散射截面，拉曼光谱的应用在很长一段时间内受到了限制。为此，人们发展了基于共振增强和表面增强两种技术来获得增强的拉曼信号。但是，共振增强对分子的选择性,表面增强很难获得本征的信号,因此如何获得均匀、重复和廉价的拉曼增强活性基底等仍是目前拉曼光谱研究中的挑战性问题。为解决拉曼活性基底的均一性以及如何利用因表面等离子体振荡而导致局域增强的电场等问题，本项目提出将近年发展起来的准二维原子晶体（如石墨烯、氮化硼、硒化铟等）应用到表面增强拉曼光谱的研究中，发展平整基底上的拉曼信号增强技术，探索其在化学反应过程和催化反应机理研究中的应用。同时，以"柔性拉曼活性基底"的制备为主线，系统探索平整基底上的拉曼信号增强技术在各种表面上检测微量物质等方面的应用。

本项目的主要目标是发展平整基底上的拉曼信号增强技术并探索其在催化反应机理研究和原位痕量分析等方面的应用。研究内容主要包括：1）二维原子晶体材料作为拉曼信号增强基底及其增强机理研究；2）平整基底上的局域表面等离子体共振的实现与表征；3）基于平整基底的表面增强拉曼光谱分析方法；4）平整表面上的拉曼信号增强技术在化学反应过程和催化反应机理研究中的应用；5）柔性平整基底上的拉曼信号增强技术的无损与原位在线分析方法。.通过项目的实施，我们系统研究了石墨烯以及其他不同属性二维材料的化学增强机理；研究了各向异性二维原子晶体的光学各向异性以及表面增强拉曼散射效应；研究了石墨烯包覆金属纳米粒子的制备及其在表面增强拉曼光谱中的应用；发展了基于G-SERS柔性平整基底的定量分析方法，研究了其在化学反应检测和催化反应中的应用；建立了电化学-表面增强拉曼光谱联用装置研究表面有机反应的技术。.项目共发表学术论文51篇，其中影响因子大于7的高影响力论文35篇，申请和授权专利8项；参加国内国际学术会议83人次，其中邀请报告53人次；培养博士研究生22名，硕士研究生11名，出站博士后6名；研究生获奖52人次，其中国家奖学金6人次。1人入选教育部长江学者特聘教授，1人获国家杰出青年基金资助。2人入选国家“万人计划”科技创新领军人才，2人入选科技部科技创新人才推进计划中青年科技领军人才。