Printed polymer transistors

Integrated plastic circuits (IPCs) based on organic field-effect transistors (OFETs) have many advantages. One potential is the use for commercial applications such as low cost ident-tags or electronic barcodes. In order to achieve low production cost, the transistors must be prepared by printing processes. In this paper we present OFETs and organic inverters based on functional polymers with single layers applied by pad and screen printing, The pad printing technique is an efficient method for patterning the electrodes of an OFET. With this technique, dimensions of 20 mum were reached. Source-drain and gate electrodes consisting of either polyaniline, carbon black conductive ink, gold, or silver filled ink were printed. With these structures OFETs were assembled, in which poly(3-alkylthiophene) served as the semiconductor, and poly(4-hydroxystyrene) as the insulator. These polymers were deposited homogeneously by screen printing or spin coating. In addition, a gate dielectric for an OFET was also pad printed. A full organic inverter with all elcctrodes printed is introduced. As the production speed of the presented printing techniques has the ability to be scaled up, the potential for high volume printing of organic electronics is proven.