Photocurable Polyimide Gate Insulator for Pentacene Thin-Film Transistor With Excellent Chemical Resistance by Low Temperature Processing

Abstract

We introduce a photo-curable polyimide-based gate insulator for organic thin-film transistors (OTFTs) that allows low-temperature and solution-based processing and provide low leakage current density and high field-effect mobility in devices. Organic gate insulator (PI-TTE) was prepared from a blend of 75.2 wt% hydroxyl group containing polyimide (PI) and 23.8 wt% trimethylolpropane triglycidyl ether as the crosslinker, 0.5 wt% benzoyl peroxide, and 0.5 wt% triphenylsulfonium triflate as the photoacid generator (PAG). PI-TTE showed extremely low leakage current density as 2.33 × 10−10 A/cm2 at 3.3 MV/cm and exhibited a very stable capacitance (96.74 pF/mm2) and it is unchangeable up to 600 hrs. Pentacene TFT using PI-TTE as a gate dielectric showed a field effect mobility as 0.203 cm2/Vs and an on/off ratio of 1.55 × 105 with almost no hysteresis.