Rapid Synthesis of Silver Nanowires and Network Structures under Cuprous Oxide Nanospheres and Application in Surface-Enhanced Raman Scattering

Abstract

Crystalline silver nanowires, with diameters of 50–500 nm and lengths up to tens of micrometers, have been successfully synthesized by a simple wet chemical route by using cuprous oxide nanospheres as a reductant and directional agent. The products are characterized by powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, and UV–vis absorption spectroscopy. The two-dimensional netlike nanostructure is composed of several silver nanowires. The possible mechanism for the formation of silver nanowires is discussed. It is found that the architecture of silver crystals is drastically influenced by the concentration of the precursors and the reaction temperature. The experimental results reveal that the Cu2O nanospheres might play the two roles during the growth process of silver nanowires. Except for a reducing agent, Cu2O nanospheres act as a growth substrate to induce the formation of silver nanowires and a two-dimensional netlike nanostructure. Furthermore, the obtained two-dimensional netlike silver nanostructure can be used as surface-enhanced Raman scattering (SERS) substrates with high SERS activity and stability for detecting Rhodamine 6G (R6G) molecules. The analytical enhancement factor on the two-dimensional netlike silver nanostructure substrate is about 8 × 1010. Compared with other morphologies of silver substrates, it is found that the two-dimensional netlike silver nanowires exhibit the highest SERS sensitivity. Hence, SERS substrates of the two-dimensional netlike silver nanowires described in this work have potential applications in chemical and biological analysis as well as medical detection.