Fabrication and characterization of transparent conducting reduced graphene oxide/Ag nanowires/ZnO:Ga composite thin films on flexible substrates

Abstract

In recent years, flexible transparent conducting films (TCFs) have attracted considerable research interest because they are essential materials in flexible optoelectronic devices, which are still limited by the lack of suitable electrode materials. In this study, a highly stable, transparent, and a flexible composite electrode was developed using reduced graphene oxide (rGO)/silver nanowires (AgNWs)/Ga-doped zinc oxide (GZO) composite thin films. The rGO film was the first spin coated on flexible substrates and used as an adhesion enhancement layer. The AgNWs, which were used as a primary conductor, formed a random percolating network embedded between the rGO and GZO films. The GZO film was sputtered on the surface of the AgNWs and was used as a protective layer to prevent the oxidation of the AgNWs. The rGO/AgNWs/GZO composite thin film exhibited excellent electrical conductivity and superior stability to a monolayer or a bilayer TCF. The sheet resistance of the composite film (5.45 ± 0.41 Ω/□) slightly increased to no more than 5% when exposed to the atmosphere for 60 days. The rGO/AgNWs/GZO composite film exhibited an optical transmittance of approximately 85% at a wavelength of 550 nm. A bending test was conducted for 600 cycles with a curvature radius of 1 cm, and the test results revealed that sheet resistance of the composite film varied by less than 10%. The developed rGO/AgNW/GZO transparent conducting thin films have potential for use in future flexible optoelectronic device applications.