基于有序银纳米火山阵列的柔性SERS基底的构筑及其对痕量爆炸物的检测

Currently, the trace explosives detection using surface enhanced Raman scattering (SERS) is hindered by the lack of cost-efficient and highly reproducibility fabrication methods for highly uniform flexible substrates. Thus this project addresses these challenges by developing a low-cost convenient nanotechnique to fabricate large-area flexible silver nano-volcano arrays (SNVAs) templated by ordered nanomembranes as robust SERS substrates for trace explosives detection on real-world surfaces. Project planning includes the following: (i) Fabricating and tailoring large-area, highly ordered SNVAs, and discussing the formation mechanism of self-assembled SNVAs and factors influencing their formation. (ii) Studying the localized surface plasmon resonance of the SNVAs with tailored topographies, investigating the influence of the excitation wavelength on the SERS, and exploring theoretical origin of SERS based on SNVAs. (iii) Collecting and detecting trace explosives by simply nondestructive methods, investigating the influence of the topography of SNVAs on SERS detection, and studying the dynamic range of the observable concentration dependencies. Specific objectives are to design and construct sensitive and reproducible SERS substrates for trace explosives detection and analysis, propose an appropriate electromagnetic model for the island film system, and develop and optimize methodologies for rapidly detecting trace explosives on real-world surfaces. Therefore, the project offers a promising platform for SERS-based molecular sensors, further increases understanding of plasmonic and field localization effects in periodic nanostructures, and provides a potential capability for trace explosives detection in homeland security and crime scene investigation.

针对基于表面增强拉曼散射（SERS）效应的痕量爆炸物检测中的关键问题，即SERS基底问题，本项目预利用模板法构筑大面积有序可控的柔性银纳米火山阵列作为强健的SERS基底，探索利用其对痕量爆炸物快速检测的方法。主要包括：构筑和调控银纳米火山阵列，并探讨其形成机理和影响因素；研究其结构演化与其局域表面等离激元共振的关系，探究激发波长对SERS效应的影响，探寻该体系的SERS理论本源；探索通过简单的非破坏性手段直接对待测物体表面痕量爆炸物进行快速提取和检测的方法，研究基底形貌与检测效果的联系，明确其动态响应范围。旨在获得可用于痕量爆炸物检测的SERS基底及其构筑方法，提出适当的理论模型解释该研究体系，发展对现实表面痕量爆炸物进行快速检测的技术。最终为基于SERS效应的分子传感器提供材料基础，增进对纳米结构中等离激元和电场局域效应的认识，为国土安全和犯罪现场勘查中痕量爆炸物的检测提供实验依据。

针对基于表面增强拉曼散射（SERS）效应的痕量爆炸物检测中的关键问题，即SERS基底问题，本项目利用模板法构筑大面积有序可控的柔性银纳米火山阵列作为强健的SERS基底，并提出了利用其对痕量爆炸物快速检测的方法。研究发现利用本项目所提出的简单廉价的方法能够轻而易举的实现厘米级别的高度有序的银纳米火山阵列的制备，并且其颗粒密高达E10 cm-2以上。其空心结构的形成可归因于表面成核效应和阴影效果共同作用，并且当沉积速率较高或是较低时均不利于空心银纳米火山阵列的形成。另外，通过调节模板的氧化电压和拓孔时间，能够对银纳米火山阵列的形貌进一步调控。相较于实心银纳米火山，空心的银纳米火山的等离激元共振特性表现出更高的可调谐性。当氧化电压为60 V时，吸收带几乎覆盖整个可见区。SERS基底的最大的增强因子高达E7，信号偏差控制在5 %内，动态响应范围为E-10到E-6 M。该柔性基底能够实现直接对待测物体表面痕量爆炸物进行快速提取和检测，检测极限为100 ng/cm2。本研究为基于SERS效应的分子传感器提供材料基础，增进对纳米结构中等离激元和电场局域效应的认识，为国土安全和犯罪现场勘查中痕量爆炸物的检测提供实验依据。