Polarization characteristics in polyelectrolyte thin film capacitors Targeting field-effect transistors and sensors

Abstract: Polymers are very attractive materials that can be tailored for specific needs and functionality. They can for instance be made electrically insulating or (semi)conducting, with specific mechanical properties. Polymers are often processable from a solution, which enables the use of low-cost manufacturing techniques to fabricate polymer devices. Polymer-based electronic and electrochemical devices and sensors have been developed.This thesis is related to the polarization characteristics in polyelectrolyte thin film capacitor structures. The polarization characteristics have been analyzed at various humidity levels for polyelectrolyte capacitors alone and when incorporated as the gate-insulating material in polyelectrolyte-gated organic field-effect transistors. Both limitations and possibilities of this class of transistors have been identified. Also, a concept for wireless readout of a passively operated humidity sensor circuit is demonstrated. The sensing mechanism of this sensor is related to the polarization in a polyelectrolyte thin film capacitor. This sensor circuit can be manufactured entirely with common printing technologies of today and can be integrated into a low-cost passive sensor label.