Size-controlled synthesis of silver micro/nanowires as enabled by HCL oxidative etching

Abstract

The polyol method has been widely employed for the synthesis of uniform silver nanowires (Ag NWs) in high yields. In this article, we describe the utilization of HCl oxidative etching as an effective strategy to control the width of Ag NWs produced by the polyol approach. More specifically, the width of the produced Ag NWs could be tuned from 65 to 765 nm by varying the HCl concentration in the polyol recipe. Our results indicate that the obtained widths displayed a linear and steady increase according to the HCl concentration employed in the reaction. Although the width was also dependent on other experimental parameters such as the AgNO₃ and polyvinylpirrolidone (PVP) concentrations and temperature, the HCl oxidative etching enabled the controlled synthesis of Ag NWs over the widest range of widths. The size-dependent optical property investigations revealed that the transverse mode surface plasmon resonance peak for the produced Ag NWs red-shifted from 378 to 467 nm as their width increased from 77 to 584 nm. The application of Ag NWs (77 nm) as SERS substrates for the detection of 4-mercaptopyridine was also demonstrated. As the properties of metal nanostructures are strongly dependent upon size, the results reported herein can have important implications for designing the synthesis of uniform Ag NWs in high yields displaying controlled and/or desired dimensions for applications in areas including plasmonics, electronics, and sensing.