Low-voltage operated organic thin-film transistors with mobility exceeding 10 cm2/vs

In this letter, low-voltage operation and high mobility are simultaneously achieved in the OTFTs based on an elaborately constructed tri-layer gate dielectric. The tri-layer gate dielectric consists of the cross-linked poly(4-vinylphenol) (CL-PVP), polyvinylpyrrolidone (PVPy) and poly(styrene) (PS) films. The ultrathin CL-PVP and PS films prevent the charges transferring and trapping in the PVPy dielectric, which improves the performances. The low trap density at the organic semiconductor/dielectric interface contributes to the low-voltage operation and high mobility in the OTFTs. The OTFTs exhibit promising performances with high mobility exceeding 10 cm2/vs, small subthreshold swing of 185 mV/decade on average, high on/off ratio of $10^{{5}}$ , at low operating voltages below 5 V. The measurements on stability and ageing of the OTFTs indicate that the encapsulation is required for practical application.