Free‐Standing Conducting Polymer Films for High‐Performance Energy Devices

Thick, uniform, easily processed, highly conductive polymer films are desirable as electrodes for solar cells as well as polymer capacitors. Here, a novel scalable strategy is developed to prepare highly conductive thick poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate (HCT‐PEDOT:PSS) films with layered structure that display a conductivity of 1400 S cm −1 and a low sheet resistance of 0.59 ohm sq −1 . Organic solar cells with laminated HCT‐PEDOT:PSS exhibit a performance comparable to the reference devices with vacuum‐deposited Ag top electrodes. More importantly, the HCT‐PEDOT:PSS film delivers a specific capacitance of 120 F g −1 at a current density of 0.4 A g −1 . All‐solid‐state flexible symmetric supercapacitors with the HCT‐PEDOT:PSS films display a high volumetric energy density of 6.80 mWh cm −3 at a power density of 100 mW cm −3 and 3.15 mWh cm −3 at a very high power density of 16160 mW cm −3 that outperforms previous reported solid‐state supercapacitors based on PEDOT materials.