High-capacitance ion gel gate dielectrics with faster polarization response times for organic thin film transistors

High-capacitance ion gel-gates organic thin-film transistors (GEL-OTFT) with faster polarization response times, was demonstrated to operate frequencies up to 1 kHz. The capacitance-voltage (C-V) measurements on the ion gels at 10 Hz shows that the capacitance of metal-insulator-semiconductor (MIS) structure increases upon sweeping the bias applied to the top copper contact. The approximately equivalent amounts of injected and removed charge indicate that deep trapping of holes is not significant. The results also show that [EMIM][TFSI]-based GEL-OTFT can track 1 kHz input signal-based OTFTs. The bimodal drain current response suggests quick and short-range motions of cations and anions near the interfaces and slow ionic diffusion over longer distances. It is also maintained that short-range motion of cations and anions in the gel near the gel/semiconductor interface is responsible for the fast response.