Ingenious Method for Rapid Fabrication of a Highly Conductive Hybrid Film of Printed Cu Nanoparticle Layers Plated by Ag Nanoplates on a PET Substrate at Room Temperature

Fabrication of low-cost flexible electronics on polymeric substrates at room temperature is still a significant challenge. This study proposes a simple yet ingenious approach for fast fabrication of a highly conductive Cu–Ag hybrid film consisting of a base layer of bimodal Cu nanoparticles (NPs) and thereon a dense layer of Ag nanoplates (NPLs) by means of a combined process of printing and immersion plating in aqueous AgNO3 solution at room temperature within a few seconds. The unique structure of bimodal-sized Cu NPs with average sizes of 9 and 160 nm, respectively, enables the tunable growth of Ag NPLs on Cu NPs, during which small Cu NPs catalyze the displacement reaction of Ag ions and large ones promote anisotropic growth of Ag NPLs. This consequently results in the formation of surfactantless Ag NPLs with basal planes of {111} standing erect on the surface of the printed Cu NP film. The obtained Cu–Ag hybrid film circuits on the poly(ethylene terephthalate) (PET) substrate show a low resistivity of 14 μΩ·cm and high mechanical reliability when subjected to 10 000 bending cycles.