• Takaishi, K.
• Muto, T.
• Ribierre, Jean Charles
• Ghosh, S.
• Aoyama, T.

Abstract

<jats:p>Solution-processed ambipolar organic field-effect transistors based on dicyanomethylene-substituted quinoidal quaterthiophene derivative [QQT(CN)4] are fabricated using various gate dielectric materials including cross-linked polyimide and poly-4-vinylphenol. Devices with spin-coated polymeric gate dielectric layers show a reduced hysteresis in their transfer characteristics. Among the insulating polymers examined in this study, a new fluorinated polymer with a low dielectric constant of 2.8 significantly improves both hole and electron field-effect mobilities of QQT(CN)4 thin films to values as high as 0.04 and 0.002 cm<jats:sup>2</jats:sup> V<jats:sup>−1</jats:sup> s<jats:sup>−1</jats:sup>. These values are close to the best mobilities obtained in QQT(CN)4 devices fabricated on SiO<jats:sub>2</jats:sub> treated with octadecyltrichlorosilane. The influence of the metal used for source/drain metal electrodes on the device performance is also investigated. Whereas best device performances are achieved with gold electrodes, more balanced electron and hole field-effect mobilities could be obtained using chromium.</jats:p>

Topics

• impedance spectroscopy
• polymer
• chromium
• thin film
• dielectric constant
• gold