Low-voltage operation of a pentacene field-effect transistor with a polymer electrolyte gate dielectric

Large operating voltages are often required to switch organic field-effect transistors (OFETs) on and off because commonly used gate dielectric layers provide low capacitive coupling between the gate electrode and the semiconductor. We present here a pentacene OFET gated by a solution-deposited polymer electrolyte film in which the current was modulated over four orders of magnitude using gate voltages less than 2 V. A subthreshold slope of 180 mV per decade of current was observed during transistor turn on at a source-drain bias of -1 V; the estimated dielectric layer specific capacitance was 5 μF cm2. Sweep rate-dependent hysteresis may be attributed to a combination of ion migration and charge carrier trapping effects. Strategies to improve switching speeds for polymer electrolyte-gated OFETs are also discussed.