Facile synthesis of Cu–Ag hybrid nanowires with strong surface-enhanced Raman scattering sensitivity

Abstract

Cu–Ag hybrid nanowires with well-defined Ag nanoparticles on the surface of Cu NWs were successfully prepared by a mild two-step method. High-resolution transmission electron microscopy (HRTEM) results indicated that the as-prepared silver nanoparticles (Ag NPs) with an average diameter of 8.4 nm were directly grown on the surface of the copper nanowires (Cu NWs) through an in situ substitutional reaction with Cu–Ag metallic bonds formed between Ag NPs and Cu NWs. Growth evolution results showed that the Ag nanoseeds were prone to grow into Ag NPs when the ratio of Cu to Ag was small while they tended to grow into Ag nanowires (NWs) as the ratio of Cu to Ag dramatically increased. Furthermore, the strong surface-enhanced Raman scattering sensitivity (SERS) effect of the as-prepared Cu–Ag hybrid NWs was verified using Rhodamine 6G (R6G) and 4-aminothiophenol (4-ATP) probes.