Flexible high mobility pentacene transistor with high-k/low-k double polymer dielectric layer operating at −5 V

We report on the fabrication of pentacene-based thin-film transistors (TFTs) with a 230 nm-thick double polymer dielectric composed of 30 nm-thin low-k poly-4-vinyphenol (PVP) and 200 nm-thick high-k poly(vinylidene fluoride/trifluoroethylene) [P(VDF–TrFE)] dielectric on polyethersulfone (PES) films. Our 230 nm-thick double (high-k/low-k) polymer showed a good dielectric strength of ∼2 MV/cm, a high capacitance of 26 nF/cm2 with k = ∼7. Based on this double polymer dielectric, our flexible pentacene TFT displayed a high saturation mobility of 1.22 cm2/V s, a threshold voltage of −2.5 V, and on/off ratio of 103, stably operating under −5 V.