title: Enhancement of field-effect mobility due to structural ordering in poly(3-hexylthiophene) films by the dip-coating technique.
abstract: Organic field-effect transistors (OFETs) were fabricated by depositing a regioregular poly(3-hexylthiophene) (P3HT) active layer using a dip-coating method. The field-effect mobility in OFETs depends on chain orientation and crystallinity and is related to direction and withdrawal speed with respect to the source/drain orientation. In this paper, how to control the structural and transport properties of P3HT films by coating parallel and perpendicular to the dipping direction is demonstrated. X-ray diffraction curves taken in the perpendicular direction exhibit a higher degree of crystalline ordering and edge-on conformation compared with those in the parallel direction; this finding correlates with the directional anisotropy of the OFET mobility. Both structural anisotropy and transport properties are enhanced upon thermal treatment.
authors.affiliation: Department of Physics, University of Siegen, Walter-Flex-Strasse 3, Siegen, 57072, Germany.
authors.forename: Kamran
authors.initials: K
authors.lastname: Ali
authors.forename: Ullrich
authors.initials: U
authors.lastname: Pietsch
authors.forename: Souren
authors.initials: S
authors.lastname: Grigorian
keywords: electrical anisotropy; grazing-incidence X-ray diffraction; structural anisotropy
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