Highly flexible, transparent Cu nanowire embedded hybrid film

Abstract

Flexible transparent electrode, which is a part of OLED, solar cell, touch screen, display and other electronic devices, is one of the crucial future technologies. For transparent electrodes, ITO has been the key material, but Indium is one of the rare earth metal which is expensive. Also ITO lacks flexibility, and cracks easily, resulting severe drop of conductivity when it is bent.To overcome these drawbacks, there has been many studies about silver nanowires. However, silver has similar price with ITO, and it is small in quantity.Therefore, in this study, a copper nanowire is studied which is abundant and cheap. A copper nanowire is synthesized by hydrothermal method, and this method does not require materials. However, a copper nanowire has oxidation problem, so the nanowire is embedded in a polymer film.Chosen polymer was Glass Fabric Reinfoced film(GFR film) that shows high transparency, low Coefficient of Thermal Expansion(CTE), low retardation and low O2/H2O permeability. By embedding the nanowire, roughness decreased and oxidation resistance increased. This copper nanowire / polymer hybrid film showed high transparency, conductivity and flexibility. Finally, hybrid film was used to fabricated OLED, and compared to ITO based OLED, hybrid film showed similar performance.