Polyimide/Ta2O5 nanocomposite gate insulators for enhanced organic thin-film transistor performance

This study reports the preparation and characterization of polyimide/Ta2O5 nanocomposite films as insulators for organic thin-film transistors (OTFTs). The degree of imidization, thermal, electrical, and surface properties of the nanocomposite films were characterized as a function of Ta2O5 precursor contents. The nanocomposite films, with controlled/comparable insulator electrical characteristics and surface properties, have been found to enhance dielectric constant compared to pristine polyimide films, which resulted in improved pentacene TFT performance by a factor of 2–3 with carrier mobility values as high as 0.38 cm2/V s.

• In situ formation of Ta2O5 nanocomposite polyimide films as insulators was studied.
• Films imidization degree was characterized as a function of Ta2O5 precursor contents.
• Increase of dielectric constant of these Ta2O5/polyimide films was observed.
• Improved pentacene mobility in OTFTs by a factor of 2–3 was achieved.
• Good current on/off ratio (>105) and low threshold voltage (−1.5 V) was also obtained.