title: Synthesis and characterization of polystyrene brushes for organic thin film transistors.
abstract: We synthesized and characterized polystyrene brushes on a silicon wafer using surface-initiated atom transfer radical polymerization. The thickness of the polymer brush was controlled by adjusting the reaction time. We investigated monomer conversion as well as the molecular weight and density of the polymer brushes. When the monomer conversion reached 100%, the number-average molecular weight and film thickness reached 135,000 and 113 nm, respectively. The estimated densities of the synthesized polystyrene brushes were in the range 0.34-0.54 chains/nm2, high enough to be categorized in the "concentrated brush" regime. The synthesized polymer brush was used as an insulating layer in an organic thin-film transistor. Organic thin-film transistors were fabricated using pentacene as an active p-type organic semiconductor and a polystyrene brush on a SiO2 layer as a gate dielectric. The pentacene based organic thin-film transistor with the polystyrene brush exhibited a field-effect mobility microFET of 0.099 cm2/(V x s).
authors.affiliation: Department of Chemistry, and Chemistry Institute for Functional Materials, Pusan National University, Busan 609-735, Republic of Korea.
authors.forename: Do-Hoon
authors.initials: DH
authors.lastname: Hwang
authors.forename: Akihiro
authors.initials: A
authors.lastname: Nomura
authors.forename: Jeongsik
authors.initials: J
authors.lastname: Kim
authors.forename: Ji-Hoon
authors.initials: JH
authors.lastname: Kim
authors.forename: Hyunduck
authors.initials: H
authors.lastname: Cho
authors.forename: Changhee
authors.initials: C
authors.lastname: Lee
authors.forename: Kohji
authors.initials: K
authors.lastname: Ohno
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Tsujii