University of Minnesota-Twin Cities MRSECTimothy P. Lodge DMR-0212302Low Voltage Operation of Organic Thin Film Transistors with a Solution Processed Polymer Electrolyte Gate Insulator (IRG 2) In the past year, graduate student Matt Panzer demonstrated that it is possible to achieve both low voltage operation and very high two dimensional carrier densities in organic thin film transistors (OTFTs) employing a solution processed, solid polymer electrolyte as the gate dielectric, Figure 1. Low voltage operation of OTFTs is critical to future applications in plastic electronics, but has not been possible with more conventional gate insulators such as SiO2 that have specific capacitances of 10-20 nF/cm2. By contrast, polymer electrolytes such as PEO/LiClO4 can provide specific capacitances in excess of 100 µF/cm2, resulting from the migration of ions within the electrolyte. Thus, using PEO/LiClO4 it is possible to induce carrier densities 104 times greater than for SiO2 gate dielectrics at the same applied gate voltage, which dramatically boosts source-to-drain current in an OTFT. Figure 1 shows a comparison of polymer electrolyte gated and SiO2 gated OTFTs based on the polymer semiconductor poly(3-hexylthiophene), in which higher currents are produced at far lower voltages for the polymer electrolyte gated device.