Photo-patternable polyimide gate insulator with fluorine groups for improving performance of 2,7-didecyl[1] benzothieno[3,2-b][1]benzothiopene (C_(10)-BTBT) thin-film transistors

摘要

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 photosensitive 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 ℃, has a dielectric constant of 2.8 at 10 kHz, and leakage current density of ＜1.6 × 10~(-10) A/cm~2 while biased from 0 to 90 V. To investigate the potential of the polyimide with fluorine groups as a gate insulator, we fabricated C_(10)-BTBT TFTs. The field-effect mobility and the on/off current ratio of the TFTs were measured to be 0.76 ± 0.09 cm~2/V s and ＞10~6, respectively.