Roll‐to‐Roll Fabrication of Flexible Orientated Graphene Transparent Electrodes by Shear Force and One‐Step Reducing Post‐Treatment

Abstract Flexible transparent electrodes (FTEs) are core sections for wearable photoelectric devices. However, the inevitable poor mechanical stability and expensive cost limit that the indium tin oxide FTEs are ineligible for future devices. In this work, the shear force of slot‐die printing during roll‐to‐roll process is creatively applied to form thin layer of reduced graphene oxide (RGO) for fabricating oriented poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate:RGO composite. The hydroiodic acid post‐treatment can remove insulating content of conductive polymer as well as reduce the graphene oxide to enhance the conductivity of FTEs to 1949 S cm⁻¹ with a sheet resistance of 51 Ω □⁻¹ and 82% transmittance. In addition, these FTEs demonstrate remarkable flexural endurance even under extreme bending situation. The FTEs possess a low cost of only 2.8 $ for per square meter due to the carbon materials and roll‐to‐roll technologies. Finally, the FTEs are faultlessly employed in polymer solar cells with a power conversion efficiency of 8.32% based on 1.01 cm² effective area.