Photo-patternable polyimide gate insulator with fluorine groups for improving performance of 2,7-didecyl[1]benzothieno[3,2-b][1]benzothiopene (C10-BTBT) thin-film transistors

Abstract

Surface properties of gate insulators strongly affect the device performance of organic thin-film transistors (OTFTs). To improve the performance of OTFTs, we have developed photo-sensitive polyimide gate insulator with fluorine groups. The polyimide gate insulator film could be easily patterned by selective UV exposure without any photoinitiator. The polyimide gate insulator film, fabricated at 130°C, has a dielectric constant of 2.8 at 10kHz, and leakage current density of <1.6×10−10A/cm2 while biased from 0 to 90V. To investigate the potential of the polyimide with fluorine groups as a gate insulator, we fabricated C10-BTBT TFTs. The field-effect mobility and the on/off current ratio of the TFTs were measured to be 0.76±0.09cm2/Vs and >106, respectively.