贵金属微纳球壳阵列构筑、表面增强Raman散射性能及对多氯联苯的检测

The key impediment for the practical detection of polychlorinated biphenyls (PCBs) based on surface-enhanced Raman scattering (SERS) sensors is the lack of robust and facile fabrication strategies for reproducible SERS substrates with large and stable Raman enhancement. In this item, novel fabrication techniques will be explored to obtain such substrates, namely micro/nanosized noble metal spherical shell arrays with a square centimeter in size, via utilizing monolayer polystyrene sphere templates. Their SERS performance and trace detection of PCBs will be systematically studied from both experimental and theoretical aspects. The main research contents are as follows: preparation of the noble metal spherical shell arrays with controllable and tunable structures (shape, size, and arrangement of the spherical shells) and their corresponding SERS activity; relationship between surface plasma resonance and SERS for these arrays; effect of excitation wavelength on SERS activity during Raman analysis; structurally SERS enhancement mechanism; surface decoration of spherical shells for selectively capturing PCBs; SERS signal evolution with the concentration of PCBs by adopting the optimal substrate after surface decoration. Finally, the structure-optimized noble metal spherical shell array and the efficient surface modification agent will be achieved, which enable the rapid detection of trace PCBs in environment. Also, this study will provide a new basic material for the SERS-based sensors and accelerate the actural application of noble metal spherical shell arrays.

针对基于表面增强拉曼散射（SERS）效应的多氯联苯（PCBs）检测中的关键问题，即高SERS活性衬底问题，以聚苯乙烯单层胶体晶体为模板，构筑平方厘米量级贵金属微纳球壳阵列，研究其SERS效应，探究其对PCBs的敏感特性。主要包括：不同结构（排列周期、单元形态与尺寸等）、成分的贵金属微纳球壳阵列的合成、控制及其对SERS活性的影响；研究阵列体系的表面等离子体共振（SPR）效应及其与SERS的关联；考察SERS效应与激发波长的关系；阐明SERS结构增强机理；探寻对PCBs分子高效敏感的阵列表面修饰技术；揭示PCBs浓度与SERS信号间关系。旨在获得具有高SERS活性的贵金属微纳球壳阵列衬底及其构筑方法；揭示阵列SERS效应的增强机理；发展表面修饰技术。为基于SERS效应的PCBs痕量检测提供材料基础，为贵金属微纳球壳阵列的器件化和实用化提供近期可实现性。

多氯联苯(PCBs)是首批列入国际公约的严控的持久性有机污染物，给人类健康和生态环境造成了极大威胁，其监控迫在眉睫。表面增强拉曼散射(SERS)效应具有灵敏度好和效率高等优点，有望实现PCBs的快速、痕量检测。SERS检测PCBs的信号增强能力和灵敏度是待解决的关键问题。本项目主要针对高活性衬底制备和提高检测信号灵敏度两方面开展工作。衬底方面，我们以聚苯乙烯单层胶体晶体为模板，按照项目提出的“自下而上”与“自上而下”结合的合成策略，“自下而上”先采用离子束溅射镀膜获得表面光滑的金/银球壳阵列，然后“自上而下”采用了物理工艺（等离子体）和一些化学工艺（电泳、置换反应和氧化石墨烯修饰等）处理球壳，构筑了平方厘米量级壳层粗糙多孔的金/银微纳球壳阵列，评估了它们的SERS性能，并与其它模板（静电纺丝薄膜和ZnO纳米棒阵列）合成的同类衬底进行性能比较，获得了几类信号均匀的高活性的SERS基底（纳米多孔金/银球壳阵列，粗糙银球壳阵列、银球形纳米颗粒/氧化石墨烯片三明治结构、银枝晶/ZnO纳米棒异质阵列等）。信号灵敏度方面，考察了氧化石墨烯和巯基环糊精修饰衬底前后PCBs的检测效果，结果表明，二者一定程度上提高了基底对PCBs的富集，增强了SERS检测PCBs的敏感性（最低探测浓度可达1 nM量级）。这些工作为SERS效应检测PCBs提供了科学依据和技术支持。本项目相关研究结果已发表SCI论文9篇（一作4篇，合作6篇），第一署名申请专利2项（已授权1项），培养硕士研究生3人，较好的完成了预期目标。