Ag-coated 3D Cu(OH)2 nanowires on the woven copper mesh as a cost-effective surface-enhanced Raman scattering substrate

Abstract

The commercial development of surface-enhanced Raman scattering (SERS) technique is extremely limited to the high-cost and complex fabrication of desired SERS substrate with high SERS sensitivity and good signal reproducibility. Herein, Ag-coated three-dimensional (3D) Cu(OH)2 nanowire arrays on the woven copper mesh were fabricated by a simply in-situ chemical engraving and sputtering deposition as the promising SERS substrate. Importantly, ascribed to the large surface area, the 3D hierarchical micro-nanostructures containing dense needle-like Cu(OH)2 nanowires offer an excellent platform to load the Ag nanoparticles and enrich target molecules, which is favorable for enhancing the Raman signals of adsorbates. As a result, a limit concentration of probe molecule Rhodamine 6G (R6G) down to 0.1 pM was identified, corresponding to an average enhancement factor of 7 orders. The relative signal deviation was tested to be 17.5% for a single sample and 19.3% among 10 samples. Furthermore, thiram fungicide (a sort of pesticide) residue was also analyzed, showing a linear detection range between 0.1 mM and 50 nM. This simple, large-scale and low-cost fabrication approach offers a promising candidate of SERS chips to the practical detection of pesticide residues, food safety inspection and organic pollutants in the environment.