Efficient metallic nanowire welding using the Eddy current method

In this study, metallic nanowires (M-NWs) such as silver nanowires (AgNWs) and copper nanowires (CuNWs) were welded only at junctions resistively by a novel method using an indirect Eddy current through an inductive power transfer. By applying an inductive power of 45 kHz alternating current power indirectly for 6 s to the M-NW network deposited on polymer substrates, a decrease of sheet resistance up to similar to 67.9% for AgNWs and similar to 49.9% for CuNWs could be obtained without changing the optical transmittance. For AgNWs, after the welding a decrease of surface roughness could also be observed from 44.5 nm to 26.3 nm, which is similar to the height of a single layer AgNW (22.2 nm) for a bilayer junction. For AgNWs coated on a transparent flexible substrate, after the cyclic bending of 10 000 times, no change of resistance (Delta R/R0) of the AgNWs after the welding was observed and the welded AgNWs were not easily peeled off from the substrate. It is believed that this novel welding method can be applied not only to all kinds of M-NWs on various flexible low-temperature polymer substrates, but also to large areas at a short time and at low cost.