A 40 wt. % Fe(III) p-toluenesulfonate hexahydrate (Fe(OTs)3) solution was spin-coated onto the graphene film at 200 rpm for 30 s. This process served to pre-coat the film and facilitate optimal spreading. Subsequently, an additional spin-coating was performed at 1,000 rpm for 30 s. The film was then quickly removed and placed on a hot plate set to 50 °C for 5 minutes to prevent crystallization of the Fe(OTs)3 during drying. Vapor-phase polymerization of EDOT EDOT (200 µL) was added to a cotton ball and placed with a stir bar at the bottom of a desiccator. To maintain a constant humidity, the coated graphene film was placed in a desiccator with a water-saturated MgCl solution and a humidity sensor. A vacuum was pulled for 5 min using a membrane pump, and the desiccator was placed on a hot plate at 70 °C for two hours. Subsequently, the film was removed and annealed in an oven at 60 °C. This was then cooled and washed with ethanol to remove any residual oxidant.