Printed ion-gel transistor using electrohydrodynamic (EHD) jet printing process

Abstract

Abstract An ion-gel-based transistor was fabricated using an electrohydrodynamic (EHD) jet printing process. In general, EHD jet printing is operated in four jetting modes: dripping, micro-dripping, cone-jet and multi-jet ones. Both poly(3-hexylthiophene-2,5-diyl) (P3HT) and poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS), as a semiconductor and a gate electrode, respectively, enable successful printing in cone-jet mode and the resulting pattern widths are about 10 μm (P3HT) and 200 μm (PEDOT:PSS). On the other hand, the ion-gel electrolyte cannot be printed in cone-jet mode because of the excessive number of ions in the ink that perturb the fluidic behavior. Therefore, dripping mode was used to produce an ion-gel pattern under the application of a very low voltage, which is referred to as electrostatic-force-assisted dispensing printing. This method could make good patterns of an ion-gel and allow the fabrication of an ion-gel-based transistor. The EHD jet-printed transistor exhibited an average mobility ( μ ), threshold voltage ( V th ), on/off current ratio ( I on / I off ) and subthreshold swing ( SS ) of 0.12 ± 0.05 cm2/Vs, −0.83 ± 0.1 V, ∼10 5 and 73 ± 11 mV/decade, respectively.