A Method for Fabricating an Ultrathin Multilayer Film Composed of Poly(p‐phenylenevinylene) and Reduced Graphene Oxide on a Plastic Substrate for Flexible Optoelectronic Applications

The photoconductive properties of a uniform ultrathin multilayer film composed of alternating poly(p‐phenylene vinylene) (PPV) and reduced graphene oxide (RGO) layers, fabricated on a poly(ethylene terephthalate) (PET) sheet are reported. The assembly of the two electron‐rich layer components on the temperature‐sensitive substrate is realized using a layer‐by‐layer‐deposition technique under mild conditions and HI/H₂O vapor treatment at 100 °C. This protocol is established to simultaneously convert the layer components to their conjugated counterparts, PPV and RGO in the multilayer films, whose total thicknesses shrinks to 50% of their original values due to lattice contraction. Furthermore, the surface roughness decreases significantly, in contrast to the results obtained from general chemical treatments. The PET sheets coated with (PPV/RGO)₁₅ films exhibit a photocurrent of 115 μA at an illumination intensity of 1.1 mW and a photoresponsivity of 111.1 mA W^?1 at an illumination intensity of 0.5 mW; these are among the best values yet achieved in carbon‐based materials. The establishment of a method for fabricating (PPV/RGO) films on a temperature‐sensitive transparent flexible sheet is crucial for the development of organic‐based portable electronic devices.