Roles of graphene nanogap for the AgNFs electrodeposition on the woven Cu net as flexible substrate and its application in SERS

A new substrate composing of Ag nanoflowers on graphene@Cu net (AgNFs/G@Cu) was fabricated on the flexible woven copper net. Graphene, an ideal 2D plane, provides better dispersion of regular electrodeposited AgNFs arrays. Graphene nanogap was used to enhance the EM coupling between AgNFs and metal Cu substrate. Regular AgNFs arrays offer denser “hotspots”, which further enhance the EM coupling. High sensitivity (rhodamine 6G (R6G): 10−14 M, crystal violet (CV): 10−12 M) and good homogeneity are realized in our experiment and proved by the COMSOL simulation. Cu net, remarkable flexibility and practicality, allows for a close contact to the sample surface by swabbing. Malachite green (MG) as low as 10−11 M on the surface of the marine fish can be detected. This work may offer novel and practical SERS applications in the areas of pesticide residue, food security and biotechnology.