动态调节SERS活性热点的2D贵金属纳米颗粒有序阵列/功能水凝胶体系及其应用

Traditional Surface-enhanced Raman scattering (SERS) active substrates have disadvantages that nanogaps cannot be controlled and present dynamic SERS active substrates have shortcomings of short optimal detection time and low reproducibility. In order to resolve this problem, we developed an interesting route to constitute a new dynamic SERS active substrate of two-dimensional (2D) noble metal nanoparticle array/hydrogel composite by photopolymerzing reaction solution into the metal nanoparticle array in situ. The nanogaps between adjacent nanoparticles were dynamically tuned because of volume changes of hydrogel carrier, thereby generating suitable nanogaps among metal nanoparticles on the surface of hydrogel film. We will systematically study the influence of nanogaps between adjacent metal nanoparticles on volume changes in the hydrogel film and investigate the relationship among the plasmon resonance, the electromagnetic field coupling effect and the SERS in this dynamic SERS active substrate. The motivation of this project is to develop the constitution method of the 2D noble metal nanoparticles array/hydrogel composite active substrate with good uniformity, stability and repeatability and to reveal the dependence of SERS effect on the nanogaps between adjacent metal nanoparticles. This study will not only provide design ideas and realization route for the high performance dynamic SERS active substrate, but also is important to reveal the preparation process, gap adjustable and the relationship between nanogaps and SERS effect of this new dynamic SERS active substrate.

本项目针对传统SERS基底中单元纳米间隙不可调控及现有动态SERS基底表征窗口时间短、重现性低的缺点，提出有序贵金属纳米颗粒阵列原位复合智能水凝胶薄膜，构筑新型动态SERS活性基底的策略。通过水凝胶的溶胀和收缩，实现颗粒间隙的动态调节，产生最优间距，获得最佳SERS效应。系统研究复合薄膜体积变化与颗粒间隙的关系；揭示动态SERS活性基底中纳米单元间的等离子激元共振、电磁场耦合效应与SERS之间的关联。旨在发展基于贵金属纳米颗粒有序阵列/水凝胶复合薄膜的动态SERS活性基底构建方法，实现具有良好均匀性、稳定性与可重复性动态SERS活性基底的构筑；揭示有序阵列/水凝胶复合薄膜体系中颗粒间隙距离与SERS增强特性的关联。这不仅为高性能动态SERS活性基底的设计提供设计思想与实现途径，而且对揭示这类新型动态SERS活性基底的制备过程、间隙可调控性及其间隙大小与SERS增强效应的关系具有重要的意义。

调控贵金属纳米颗粒间距是增加表面拉曼散射（SERS）信号的一种有效方法。但现有动态SERS基底由于颗粒多数呈无规分布，导致重现性较低。为此，本项目提出有序贵金属纳米颗粒阵列与智能水凝胶薄膜复合，借助阵列的高度有序性和水凝胶的可溶胀与收缩性，构筑间距可调的高稳定动态SERS基底的策略。在本研究中，通过有机模板法结合溅射沉积与高温退火技术制备了二维Au纳米颗粒阵列。将制备的二维贵金属纳米颗粒阵列与智能水凝胶复合后，研究了其动态SERS性能。结果表明，该复合基底的SERS信号随着阵列中颗粒间距的减小，逐渐增强。在最佳测试条件下，实现了对氨基苯硫酚（4-ATP）及农药残留物-福美双高敏感（两者检测极限分别为10-10和10-9 M）和高稳定性（RSD=15.2%）探测。另外，该基底具有良好的持久性。该研究工作为高稳定，高敏感SERS基底的构筑提供了一种思路与材料基础。此外，本项目还以模板法制备的二维Au纳米颗粒阵列为基底，构筑了2D Au@金属有机骨架化合物（MOFs）纳米颗粒有序阵列，实现了气体有机小分子的高敏感SERS检测。