Ag gyrus-nanostructure supported on graphene/Au film with nanometer gap for ideal surface enhanced Raman scattering

作者:Li, Chonghui; Liu, Aihua; Zhang, Chao; Wang, Minghong; Li, Zhen; Xu, Shicai; Jiang, Shouzhen; Yu, Jing; Yang, Cheng; Man, Baoyuan*
来源:Optics Express, 2017, 25(17): 20631-20641.
DOI:10.1364/OE.25.020631

摘要

The physical phenomenon, surface-enhanced Raman scattering (SERS), is mainly based on the local electromagnetic fields enhancement located at the nano-gaps between metal nanostructures attributed to localized surface plasmon resonance. Therefore, nano-gaps are very important for obtaining high-density hot spots and optimal and uniform SERS signals. However, it remains a challenge to form the three-dimensional ultra-narrow nanogaps. Here, a gyrus-inspired Gyrus-SERS substrate was fabricated with the nanostructure of Ag gyrus/graphene/Au film using an extremely simple method. The lateral and vertical hot spots respectively were obtained from the dense nano-gaps (similar to 3 nm) between gyrus and the coupling of Ag gyrus and Au film in bilayer graphene nano-gaps (0.68 nm), which were demonstrated in experiment and theory. The proposed Gyrus-SERS platform performs an excellent SERS activity (EF similar to 5 x 10(9)), high sensitivity (the minimum detected concentration of R6G and CV respectively is 10(-13) and 10(-12) M), and outstanding reproducibility (RSD similar to 7.11%). For practical application, the in situ detection of Malachite green (MG) residue on prawn skin was executed using the prepared flexible Gyrus-SERS substrate, which shows the wide potential in food safety field.