Highly ordered rectangular silver nanowire monolayers: water-assisted synthesis and galvanic replacement reaction with HAuCl(4).

We demonstrate a simple water washing process for large-scale fabrication of highly ordered and aligned rectangular silver nanowire monolayers from polyol systems. These monolayers exhibit unique structure-dependent chemical reactivities for the galvanic replacement reaction with HAuCl(4), and novel gold nanoneedle arrays with sharp tips and a uniform structure have been produced.