Recently, various studies on novel materials for transparent conductive electrodes (TCEs) such as metal meshes, metal nanowires, conductive polymers, graphene, and carbon nanotubes have been progressing actively. Among these materials, metal nanowires may have potential for flexible device applications because they can be fabricated easily by using low-cost solution-based processes. Metal nanowires, however, still have several problems to be resolved before commercialization, including a relatively high sheet resistance due to poor contacts at wire-wire junctions. Also, they have an instability problem that may lead to an increase in their electrical resistance when exposed to air for a long time due to the oxidation of metals. Therefore, decreasing the junction resistance between the metal nanowires as well as enhancing the oxidation stability may be essential for improving their performances, especially in terms of the electrical figure of merits.
In this study, we present solution processes for fabricating hybrid-type flexible copper nanowires (CuNWs) which can significantly improve their electrical properties and oxidation stability. This has been achieved by depositing CuNWs on flexible substrates via spray coating and coating the CuNWs with nickel (Ni) via electroplating. For all of the fabricated CuNWs, their surface morphologies, electric sheet resistances, visible-light transmittances and reflectances, and color properties were characterized. Furthermore, the effects of Ni coating on the wire-to-wire junction resistances of the CuNWs as well as their oxidation and corrosion stabilities were investigated.