title: Surface modification of polyimide gate insulators for solution-processed 2,7-didecyl[1]benzothieno[3,2-b][1]benzothiophene (C10-BTBT) thin-film transistors.
abstract: The surface property of a polyimide gate insulator was successfully modified with an n-octadecyl side-chain. Alkyl chain-grafted poly(amic acid), the polyimide precursor, was synthesized using the diamine comonomer with an alkyl side-chain. By adding a base catalyst to the poly(amic acid) coating solution, the imidization temperature of the spin-coated film could be reduced to 200 °C. The 350 nm-thick polyimide film had a dielectric constant of 3.3 at 10 kHz and a leakage current density of less than 8.7 × 10(-10) A cm(-2), while biased from 0 to 100 V. To investigate the potential of the alkyl chain-grafted polyimide film as a gate insulator for solution-processed organic thin-film transistors (TFTs), we fabricated C(10)-BTBT TFTs. C(10)-BTBT was deposited on the alkyl chain-grafted polyimide gate insulator by spin-coating, forming a well-ordered crystal structure. The field-effect mobility and the on/off current ratio of the TFT device were measured to be 0.20-0.56 cm(2) V(-1) s(-1) and >10(5), respectively.
authors.affiliation: Division of Advanced Materials, Korea Research Institute of Chemical Technology, 141 Gajeong-ro, Yuseong-gu, Daejeon 305-600, Republic of Korea. kjang@krict.re.kr
authors.forename: Kwang-Suk
authors.initials: KS
authors.lastname: Jang
authors.forename: Won Soo
authors.initials: WS
authors.lastname: Kim
authors.forename: Jong-Myung
authors.initials: JM
authors.lastname: Won
authors.forename: Yun-Ho
authors.initials: YH
authors.lastname: Kim
authors.forename: Sung
authors.initials: S
authors.lastname: Myung
authors.forename: Jae-Won
authors.initials: JW
authors.lastname: Ka
authors.forename: Jinsoo
authors.initials: J
authors.lastname: Kim
authors.forename: Taek
authors.initials: T
authors.lastname: Ahn
authors.forename: Mi Hye
authors.initials: MH
authors.lastname: Yi