Influence of geometry variations on the response of organic electrochemical transistors

We report on the fabrication and characterisation of entirely inkjet-printed organic electrochemical transistors (OECTs) based on poly(3,4-ethylenedioxithiophene) poly(styrenesulfonate) (PEDOT:PSS). These transistors were used to evaluate the assumed geometry-performance relationship of OECTs by changing the transistor dimensions and monitoring the output characteristics. We could show that the on-current depends on the PEDOT:PSS thickness and that the on-to-off current ratio is related to the distance between the printed electrodes. Taking these results into account, we fabricated entirely inkjet printed electrochemical inverters with a switching time of about 4 s. These inverters outline a first step from organic electrochemical transistors towards logic circuits.