Poly(4-vinylphenol-co-methyl methacrylate)/Titanium Dioxide Nanocomposite Gate Insulators for 6,13-Bis(triisopropylsilylethynyl)-Pentacene Thin-film Transistors

Poly(4-vinylphenol-co-methyl methacrylate)/titanium dioxide (TiO2) nanocomposite insulators were fabricated for application in 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS-Pn) thin-film transistors (TFTs). The capacitance of the fabricated capacitors with this nanocomposite insulator increased with increasing content of the high-dielectric-constant TiO2 nanoparticles. Nonetheless, particle aggregates, which were invariably produced in the insulator at higher TiO2 contents, augmented gate-leakage currents during device operation while the rough surface of the insulator obstructed charge transport in the conducting channel of the TIPS-Pn TFTs. These results suggest a significant effect of the morphological characteristics of nanocomposite insulators on TFT performance, as well as on their dielectric properties. Herein, the optimal particle composition was determined to be approximately 1.5 wt%, which contributed to characteristic improvements in the drain current, field-effect mobility, and threshold voltage of TIPS-Pn TFTs.