有序多孔贵金属介观晶体的制备科学及其SERS性能研究

The pesticide residues on fruits and vegetables are very harmful to human health. Surface-enhanced Raman spectroscopy provides a label-free technique for the detection of molecules by detecting their distinct signature of vibrational modes, has the potential application in detecting pesticide residues. SERS-active substrates with large-area surface morphology uniformity, stability, high enhancement factor and good reproducibility is rather difficult to achieve. Properly engineered nano-structured substrates with an ideal reproducible surface morphology in which EM hot spots can be created plentifully, reproducibly and reliably, are an important challenge. In this work, novel ordered nanoporous metal mesocrystals will be developed based on the strategy of Template-directed polyol reduction combined with the Site-specific etching. The mesocrystal formation process and self-assembly mechanism will be demonstrated by applying the technique of 3D Transmission electron microscopy. The EM field distribution and SERS-enhancement will be studied by the near-field scanning technique combined with in-site Raman detecting technique, in order to optimize the morphology and structure of nanoporous Au, Ag mesocrystals for improving their SERS properties and the limit of detection of pesticide residues. The SERS-technique with our nanoporous metal mesocrystals as active-materials can provide a rapid, high-sensitive and cost-effective way for detection of organophosphorus pesticide residues on fruits and vegetables. It is helpful to reveal the metal mesosrystal formation mechanism, and the relation among the mesocrystal structure, SPR, local field enhancement and SERS enhancement mechanism.

瓜果蔬菜农药残留超标对人体健康威胁极大。表面增强拉曼光谱能够提供物质振动信息并具有很高灵敏度，有望应用于果蔬表面低残农药快速、高灵敏度检测。如今用于检测低残农药的SERS活性材料多存在重复性和均匀性不好，增强因子不高等问题。发展形貌可控、增强性能高、重复性好且均匀的活性材料是SERS应用发展的重要挑战。本课题计划采用模板导引多元醇还原结合定点刻蚀的方法，设计与制备新型有序多孔贵金属介观晶体，采用三维透射电镜研究其介观晶体形成过程和机理；开发有序多孔Au、Ag介观晶体SERS活性材料，采用近场扫描探针和原位拉曼扫描联用技术，可视化检测介观晶体EM电场分布和研究SERS增强机理，对比DDA理论计算结果来优化其结构参数，改善其SERS性能和对有机磷农药的检测限，为开发新型低残农药高灵敏度检测技术奠定基础。促进基础理论上对金属介观晶体形成机理，以及其形貌结构与SPR特性、SERS增强机理的理解。

瓜果蔬菜农药残留超标对人体健康威胁极大。表面增强拉曼光谱能够提供物质振动信息并具有很高灵敏度，有望应用于瓜果蔬菜表面低残农药快速、高灵敏度检测。如今用于低残农药检测的SERS活性材料大多存在重复性和均匀性不好，增强因子不高等问题。发展形貌可控、增强性能好、重复性好且均匀的活性材料是SERS应用发展的重要挑战。本课题采用表面活性剂介导合成结合定点刻蚀的方法，设计与制备了新型多孔贵金属介观晶体，采用三维透射电镜揭示了其介观晶体形成过程和机理；开发了高效多孔Au、Ag介观晶体，并对其探测甲基对硫磷及莠去津的SERS性能及检测极限进行了研究，并对比DDA理论计算结果优化了其结构参数，提高了其SERS性能，其对对低残农药的检测限达到0.2ppm级别，为开发新型低残农药高灵敏度、高选择性检测技术奠定基础。促进了基础理论上对金属介观晶体形成机理，以及其形貌结构与表面等离子体共振特性、EM电场分布及SERS增强机理的理解和探索。并发现和报道了一种新型半导体SERS活性衬底材料Nb2O5，可以显著增强生物医药领域染料分子的拉曼信号，实现高灵敏检测。相关成果被数十家新闻媒体报道。项目发表标注基金支持的SCI文章22篇。其中IF≥4.0文章7篇；申请专利2项。在相关国际会议上发表邀请及口头报告4次。并取得了专利转让收益。