Large-Scale Cu Nanowire Synthesis by PVP-Ethylene Glycol Route

Abstract

Cu nanowire (NW) is a promising cost-benefit conducting material that could be considered for the development of transparent conducting films (TCF). However, the development of Cu NW as an alternating material for Ag or Au is not only limited by its stability in atmospheric conditions in the nanometer range but also due to the nonavailability of a simple synthetic route to produce them in high yields and in large-scale. Here, a scheme to synthesize Cu NWs by reducing Cu nitrate in a Cl− ion-polyvinylpyrrolidine- (PVP-) ethylene glycol (EG) system is proposed. Cu NWs with average diameter around 60 nm and average length of about 40 μm was obtained under optimized experimental conditions. Furthermore, the formation of Cu NW was elucidated to be through the progression of the following sequential reduction steps: at first, Cu ions underwent partial reduction to form spherical Cu2O. Then, the spherical Cu2O particles were redissolved and reduced to metallic Cu0 atoms that subsequently formed the Cu seeds. Thereafter, Cu seeds underwent etching to form multiply-twinned particles (MTP). Finally, these Cu MTP grew unidirectionally to form metallic Cu NWs.