title: Molecular origin of high field-effect mobility in an indacenodithiophene-benzothiadiazole copolymer.
abstract: One of the most inspiring and puzzling developments in the organic electronics community in the last few years has been the emergence of solution-processable semiconducting polymers that lack significant long-range order but outperform the best, high-mobility, ordered semiconducting polymers to date. Here we provide new insights into the charge-transport mechanism in semiconducting polymers and offer new molecular design guidelines by examining a state-of-the-art indacenodithiophene-benzothiadiazole copolymer having field-effect mobility of up to 3.6 cm(2) V(-1) s(-1) with a combination of diffraction and polarizing spectroscopic techniques. Our results reveal that its conjugated planes exhibit a common, comprehensive orientation in both the non-crystalline regions and the ordered crystallites, which is likely to originate from its superior backbone rigidity. We argue that charge transport in high-mobility semiconducting polymers is quasi one-dimensional, that is, predominantly occurring along the backbone, and requires only occasional intermolecular hopping through short π-stacking bridges.
authors.affiliation: Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA.
authors.forename: Xinran
authors.initials: X
authors.lastname: Zhang
authors.forename: Hugo
authors.initials: H
authors.lastname: Bronstein
authors.forename: Auke J
authors.initials: AJ
authors.lastname: Kronemeijer
authors.forename: Jeremy
authors.initials: J
authors.lastname: Smith
authors.forename: Youngju
authors.initials: Y
authors.lastname: Kim
authors.forename: R Joseph
authors.initials: RJ
authors.lastname: Kline
authors.forename: Lee J
authors.initials: LJ
authors.lastname: Richter
authors.forename: Thomas D
authors.initials: TD
authors.lastname: Anthopoulos
authors.forename: Henning
authors.initials: H
authors.lastname: Sirringhaus
authors.forename: Kigook
authors.initials: K
authors.lastname: Song
authors.forename: Martin
authors.initials: M
authors.lastname: Heeney
authors.forename: Weimin
authors.initials: W
authors.lastname: Zhang
authors.forename: Iain
authors.initials: I
authors.lastname: McCulloch
authors.forename: Dean M
authors.initials: DM
authors.lastname: DeLongchamp