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Introduktion til DIFO tidsskriftet Scandinavian Journal of Sport and Exercise Psychology (SJSEP).

About SJSEP Aim and Scope

In this paper, we have utilized a poly(vinylidene difluoride) poly(styrene) sulfonic acid patterned ion-conducting membrane as a platform onto which electronics based on both depletion mode and enhancement mode ion-modulated transistors have been built. The flexible membrane itself acts as both the substrate for, and the electrolyte in, the two transistor types. This is possible since the membrane is modified so that it is ion-conducting in certain places and insulating in others. The two transistor types have different semiconductors, one being conducting (the depletion mode transistor) and the other nonconducting (the enhancement mode transistor) in the normal and un-biased state. Both transistor types are potentially-driven with the crucial difference that the depletion mode transistor channel is electrochemically operated. The two transistor types are fabricated simultaneously on the same substrate, but more complicated structures such as inverters and ring-oscillators, operating at low voltages, are presented in this paper to demonstrate the usefulness of the membrane as a platform for cheap and disposable electronics.

We report a simple and roll-to-roll suitable method of manufacturing low-voltage, all-polymer electrochemical transistors (ECTs). The ECTs are built on self-supported and patterned ion conducting membranes that are tailor-made by the electron beam irradiation induced grafting technique. The redox-active poly(3,4-ethylene dioxythiophene)/poly(styrene sulfonate) (PEDOT/PSS) is then printed by flexography onto the membrane in one fabrication step. The ECTs are “normally-on” devices that operate below 2 V. We also utilize overoxidation of PEDOT in order to demonstrate write-once read many times (WORM) memory functionality in the ECT.

The concept of using ion conducting membranes (50-150 μm thick) for gating low-voltage (1 V) organic field-effect transistors (OFETs) is attractive due to its low-cost and large-area manufacturing capabilities. Furthermore, the membranes can be tailor-made to be ion conducting in any desired way or pattern. For the electrolyte gated OFETs in general, the key to low-voltage operation is the electrolyte "insulator" (the membrane) that provides a high effective capacitance due to ionic polarization within the insulator. Hydrous ion conducting membranes are easy to process and readily available. However, the role of the water in combination with the polymeric semiconductor has not yet been fully clarified. In this work electrical and optical techniques are utilized to carefully monitor the electrolyte/semiconductor interface in an ion conducting membrane based OFET. The main findings are that 1) moisture plays a major part in the transistor operation and careful control of both the ambient atmosphere and the potential differences between the electrodes are required for stable and consistent device behavior, 2) the obtained maximum effective capacitance (5 μF cm -2 ) of the membrane suggests that the electric double layer is distributed over a broad region within the polyelectrolyte, and 3) electromodulation spectroscopy combined with current-voltage characteristics provide a method to determine the threshold gate voltage from an electrostatic field-effect doping to a region of (irreversible) electrochemical perturbation of the polymeric semiconductor.

A new type of low‐voltage organic transistor is manufactured using a thick ion‐conducting membrane as gate insulator. High current output at 1 V of operation is achieved. The versatile properties of the novel insulator are shown by driving an electrochromic display pixel and a transistor on the same membrane.

We present a novel ion enhanced organic transistor using a thick, ion conducting mem-brane (MemFET). The membrane acts both as gate insulator and as mechanical sup-port. The fabrication of the membranes starts with a PVDF-film as base material, which is functionalized by the roll-to-roll suitable electron beam irradiation induced grafting technique. For comparison, we have also used the commercially available Nafionr-membrane. The MemFETs are fabricated by standard laboratory fabrication techniques using soluble conducting and semiconducting polymers. The MemFETs operate at 1 V.