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Abstract The conductive polymer poly(3,4-ethylenedioxythiphene):poly(styrenesulfonate) (PEDOT:PSS) is widely used in organic electronics and printed electronics due to its excellent electronic and ionic conductivity. PEDOT:PSS films exhibit anisotropic conductivities originating from the interplay of film deposition processes and chemical structure. The previous studies found that high boiling point solvent treated PEDOT:PSS exhibits an anisotropy of 3–4 orders magnitude. Even though both the in-plane and out-of-plane conductivities are important for the device performance, the out-of-plane conductivity is rarely studied due to the complexity with the experiment procedure. Cellulose-based paper or films can also exhibit anisotropic behavior due to the combination of their intrinsic fibric structure and film formation process. We have previously developed a conductive paper based on PEDOT:PSS and cellulose which could be used as the electrodes in energy storage devices. In this work we developed a novel measurement set-up for studying the anisotropy of the charge transport in such composite materials. A tool with two parallel plates mounted with spring loaded probes was constructed enabling probing both lateral and vertical directions and resistances from in-plane and out-of-plane directions to be obtained. The measurement results were then input and analyzed with a model based on a transformation method developed by Montgomery, and thus the in-plane and out-of-plane conductivities could be detangled and derived. We also investigated how the conductivity anisotropy depends on the microstructure of the cellulose template onto which the conductive polymer self-organizes. We show that there is a relatively small difference between the in-plane and out-of-plane conductivities which is attributed to the unique 3D-structure of the composites. This new knowledge gives a better understanding of the possibilities and limitations for using the material in electronic and electrochemical devices. Graphical abstract Image 1 Highlights • Developed a simple to use generic tool for measuring 3-D resistances of thick conducting self-standing films. • The in-plane and out-of-plane conductivities were deduced by a method developed by Montgomery. • Both CNF-PEDOT:PSS and pulp-PEDOT:PSS films exhibit anisotropic conductivity. • CNF-PEDOT:PSS films show thickness independent anisotropic conductivity. • Pulp-PEDOT:PSS became less anisotropic with increasing thicknesses. [ABSTRACT FROM AUTHOR]

Advances in organic electronics necessitates, ultrathin and miniaturized implantable energy storage modules. Here, an approach for the fabrication of on-chip, ultraflexible electrochemical capacitors is demonstrated. Two different electroactive conjugated polymers are utilized in a fabrication route that allows the patterning of finger electrodes for an ultraflexible energy storage technology. A strategy is demonstrated to realize supercapacitors with a total device thickness of 4 μm, including substrate, polymer electrode, and electrolyte. Interdigitated 20-finger electrodes from either Poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) or polythiophene functionalized with tetraethylene glycol side chains P(g42T-T), with 50 μm or 90 μm electrode spacings, are fabricated using a parylene peel off method, followed by electrolyte deposition. The miniaturized devices show 0.77 mF/cm2 areal capacitance for PEDOT:PSS and 0.06 mF/cm2 for P(g42T-T). Furthermore, the devices exhibit excellent mechanical durability, showing robust operational performance at a bending radius of 6.5 mm. [Display omitted] • Scalable fabrication route for polymer IDE structures using parylene peel off method. • PEDOT:PSS and P(g42T-T) microsupercapacitors with more than 0.6 mF/cm2 capacitance. • Ultrathin organic electronics device technology with total thickness of 4 μm. • Excellent mechanical durability, showing robust operational performance at a bending radius of 6.5 mm. [ABSTRACT FROM AUTHOR]