CAS Key Laboratory of Design and Assembly of Functional Nanostructures, and Fujian Provincial Key Laboratory of Nanomaterials, Fujian Institute of Research on the Structure of Matter , Chinese Academy of Sciences , Fuzhou 350002 , China.
Xiamen Institute of Rare Earth Materials, Haixi Institute , Chinese Academy of Sciences , Xiamen 361021 , China.
Anal Chem. 2018 Jun 19;90(12):7275-7282. doi: 10.1021/acs.analchem.8b00488. Epub 2018 May 29.
The realization of surface-enhanced Raman spectroscopy (SERS) to be a reliable quantitative analytical technique requires sensitive and reproducible enhancing substrates. Here, uniform three-dimensional (3D) Ag nanorod (AgNR) substrates with well-defined interlayer spacings are prepared through the air-liquid interface-assisted self-assembly of AgNR in a layer-by-layer manner. The correlation of the SERS performance with the 3D AgNR structures is performed by SERS mapping the substrates. SERS mapping reveals the excellent enhancement uniformity of the 3D substrates with the relative standard deviation (RSD) less than 10%. It finds that both of the number of layers (NL) and the length of the AgNR have effects on the SERS performance of the 3D AgNR substrates. It is demonstrated that the intergaps between layers contribute much to the SERS intensity of the 3D AgNR by creating the interlayer (out-of-plane) plasmonic coupling. The impact of the excitation wavelengths (532, 633, and 785 nm) on SERS performance is also determined. The optimal 3D AgNR structures achieved by the correlation study is further used to detect a set of related molecules (l-tryptophan (Trp), l-phenylalanine (Phe), urea, and melamine). The 3D AgNR SERS of the analytes exhibits linear responses over wide concentration ranges. The sensitivity of the 3D AgNR SERS is proved by comparing to that of the current methods. Moreover, the 3D AgNR substrates maintain the performance stability during 4 weeks of storage.
实现表面增强拉曼光谱（SERS）成为一种可靠的定量分析技术，需要敏感且可重现的增强衬底。在这里，通过在气液界面辅助下逐层自组装AgNR，制备了具有均匀的三维（3D）Ag 纳米棒（AgNR）和明确的层间间隔的 3D AgNR 衬底。通过对衬底进行 SERS 映射，研究了 SERS 性能与 3D AgNR 结构的相关性。SERS 映射显示出 3D 衬底具有出色的增强均匀性，相对标准偏差（RSD）小于 10%。结果表明，层数（NL）和 AgNR 的长度对 3D AgNR 衬底的 SERS 性能都有影响。结果表明，层间间隙通过创建层间（离轴）等离子体耦合对 3D AgNR 的 SERS 强度有很大贡献。还确定了激发波长（532、633 和 785nm）对 SERS 性能的影响。通过相关研究确定的最佳 3D AgNR 结构进一步用于检测一组相关分子（l-色氨酸（Trp）、l-苯丙氨酸（Phe）、尿素和三聚氰胺）。3D AgNR 对分析物的 SERS 表现出宽浓度范围内的线性响应。通过与当前方法进行比较，证明了 3D AgNR SERS 的灵敏度。此外，3D AgNR 衬底在 4 周的储存期间保持性能稳定。
