In this study, we combine a photochemical cell with a transistor, forming a novel optical-to-electronic interface using OECTs with a light-sensitive gate, which can be used for photonic, optogenetic and other applications where conversion from an optical to electronic signal is key.

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Electro-catalysis is a core element in many technologies proposed for energy storage and conversion in a post-petroleum energy landscape. This has prompted the development of new electro-catalysts, for example for fuel-cells, water-splitting cells, and metal-air batteries, which are not based on traditional rare metals such as platinum, palladium and iridium. In this context, the possibility to use organic conjugated polymers to replace inorganic catalysts has shown promising progress. We hereby demonstrate that an ''alloy'' of two conjugated polymers, poly[3,4-ethylenedioxythiophene] and polythiophenes, with different oxidation states can act as a photo-enhanced reduction catalyst for the oxygen reduction reaction and thereby reduce the overpotential for that reaction by more than 600 mV under illumination.

The discovery of a new poly(3,4-ethylenedioxythiophene) (PEDOT) composite with unique memory characteristics has led to the demonstration of durable Organic ElectroChemical Transistors (OECT) based memory devices. The composites of PEDOT with polytetrahydrofuran undergo a structural collapse during electrochemical reduction that requires approximately 800 mV overpotential to re-open and is thus hindering the re-oxidation of the composite. This effect causes the composite at intermediate potentials to be able to have two different oxidation states and thereby resistances, depending on the “on” or “off” switching potential applied prior to the intermediate potential. Notably, this hysteresis is lasting over time and no drift has been observed. Impedance spectroscopy, in-situ UV-Vis spectroscopy, conductivity measurement, in-situ electrochemical quartz crystal microbalance, and differential scanning calorimetry were used to confirm and explain the switching memory phenomena. The OECT platform was used to validate the PEDOT:PTHF as a one-pot memory source-drain material where a threefold increase in drain current was observed between “off” and “on” mode of the transistor after modulation of the Ag/AgCl gate.

Most of the techniques used for micro and nano‐patterning currently are of high quality and reproducibility, but they require expensive equipment and involve many time‐consuming steps to achieve the desired results. We herein report a patterning method of conducting layers on breathable substrates using a fast, simple, and mask‐less laser engraving technique. A resolution in the range of 30 μm has been successfully achieved in this report. The method is fast and the pattern can be easily changed or redesigned within a few minutes. The patterning time for a 25 cm2 sample is approximately 3 minutes. In comparison, patterning a sample of the same size using photolithography requires up to 4 hours. In this manuscript, we describe the laser patterning process, how to improve the patterning resolution, the calibration steps involved as well as an application for organic electrochemical transistors as gas sensors for detecting oxygen or sulphur dioxide. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42359.