title: Controllable growth and field-effect property of monolayer to multilayer microstripes of an organic semiconductor.
abstract: The controllable growth of partially aligned monolayer to multilayer micrometer stripes was demonstrated by adjusting the pulling speed in a dip-coating process. The number of molecular layers decreases with the increasing pulling speed. A lower pulling speed yields mixed multilayers (3-9 monolayers). It is noteworthy that pure monolayer and bilayer microstripes over large areas can be obtained at high pulling speeds. The stripe morphology strongly depends on the pulling speed or the number of molecular layers. XRD and confocal fluorescence measurements manifest that monolayer stripes are amorphous, while multilayer stripes (> or = 2) consist of crystalline states. FET devices were fabricated on these stripes. Monolayer stripes failed to reveal a field effect due to their amorphous state. In contrast, multilayer stripes exhibit good field-effect behavior. This study provides useful information for future molecular design in controlling molecular architectures. The controllable growth from monolayer to multilayer offers a powerful experimental system for fundamental research into the real charge accumulation and transporting layers for OFETs.
authors.affiliation: Physikalisches Institut and Center for Nanotechnology (CeNTech), Universität Münster, 48149 Münster, Germany.
authors.forename: Liqiang
authors.initials: L
authors.lastname: Li
authors.forename: Peng
authors.initials: P
authors.lastname: Gao
authors.forename: Klaus C
authors.initials: KC
authors.lastname: Schuermann
authors.forename: Stefan
authors.initials: S
authors.lastname: Ostendorp
authors.forename: Wenchong
authors.initials: W
authors.lastname: Wang
authors.forename: Chuan
authors.initials: C
authors.lastname: Du
authors.forename: Yong
authors.initials: Y
authors.lastname: Lei
authors.forename: Harald
authors.initials: H
authors.lastname: Fuchs
authors.forename: Luisa
authors.initials: L
authors.lastname: De Cola
authors.forename: Klaus
authors.initials: K
authors.lastname: Müllen
authors.forename: Lifeng
authors.initials: L
authors.lastname: Chi