Transparent conductive PEDOT–graphene films from large-flake graphite

Abstract

The demand for affordable, flexible, transparent, and robust thin film electrodes in organic electronics has highlighted the limitations of indium tin oxide (ITO), which suffers from fragility and high costs. Poly(3,4-ethylenedioxythiophene) (PEDOT), particularly when doped with poly(styrene sulfonate) (PSS), has emerged as a promising alternative due to its mechanical flexibility, electrical conductivity, and environmental stability. However, PSS's insulating nature, hygroscopicity, and acidity present significant drawbacks. This study explores an alternative approach using large-flake graphene, exfoliated through a solvent interface trapping method (SITM), as a conductive template for PEDOT polymerization. The resulting PEDOT-graphene films exhibit conductivities reaching 1070 S/cm, surpassing those of previously reported PEDOT-based films. The graphene sheets, acting as templates during vapor-phase polymerization (VPP) of PEDOT, enhance the film's conductivity by increasing electron pathways and crystalline regions within PEDOT. Characterization through SEM, TEM, XRD, Raman spectroscopy, XPS, and UV-Vis spectroscopy confirms the structural and electrical integrity of the films. Additionally, these films demonstrate potential applications in sensing technologies, particularly responsive to volatile organic compounds such as triethylamine. This work presents a scalable method for producing high-conductivity, transparent PEDOT-graphene films, offering a viable alternative to ITO in organic electronic applications.