Surface-Enhanced Raman Scattering Imaging of a Single Molecule on Urchin-like Silver Nanowires

Urchin-like silver nanowires are prepared by reacting AgNO3(aq) with copper metal in the presence of cetyltrimethylammonium chloride and HNO3(aq) on a screen-printed carbon electrode at room temperature. The diameters of the nanowires are about 100 nm, and their lengths are up to 10 mu m. Using Raman spectroscopy, the detection limit of Rhodamine 6G (R6G) on the urchin-like silver nanowire substrate can be as low as 10(-16) M, while the analytical enhancement factor is about 10(13). Raman mapping images confirm that a single R6G molecule on the substrate can be detected.