Currently, silver-nanowire-based (AgNW-based) flexible transparent electrodes exhibit the most promising performance. The electrical performance of a AgNW network depends strongly on the wire-wire junction contact. Several techniques of nanowelding or soldering have been reported to reduce the wire-wire junction resistance, but these methods may either have adverse effects on the nanowires or the substrate, or require either specific facilities or additional materials as the “solder”.

We would like to report on a new method based on capillary-force-induced cold welding. We show at nanoscale, capillary force can be used as a powerful driving force to effectively induce the self-limited cold-welding of wire-wire junctions for AgNWs. The capillary-force-induced welding can be performed by a moisture application process which is simple, fast and does not require additional materials or expensive facilities. We are able to achieve a significant improvement in electrical conductivity and flexibility, but negligible changes in transparency.

We have also demonstrated that this method is effective to heal damaged AgNW films of wearable electronics. Our capillary-force-based method may also be useful in the welding of other metal NWs and the fabrication of nanostructures or smart assemblies for versatile flexible optoelectronic applications.