title: Comparative study of microscopic charge dynamics in crystalline acceptor-substituted oligothiophenes.
abstract: By performing microscopic charge transport simulations for a set of crystalline dicyanovinyl-substituted oligothiophenes, we find that the internal acceptor-donor-acceptor molecular architecture combined with thermal fluctuations of dihedral angles results in large variations of local electric fields, substantial energetic disorder, and pronounced Poole-Frenkel behavior, which is unexpected for crystalline compounds. We show that the presence of static molecular dipoles causes large energetic disorder, which is mostly reduced not by compensation of dipole moments in a unit cell but by molecular polarizabilities. In addition, the presence of a well-defined π-stacking direction with strong electronic couplings and short intermolecular distances turns out to be disadvantageous for efficient charge transport since it inhibits other transport directions and is prone to charge trapping.
authors.affiliation: Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.
authors.forename: Manuel
authors.initials: M
authors.lastname: Schrader
authors.forename: Roland
authors.initials: R
authors.lastname: Fitzner
authors.forename: Moritz
authors.initials: M
authors.lastname: Hein
authors.forename: Chris
authors.initials: C
authors.lastname: Elschner
authors.forename: Björn
authors.initials: B
authors.lastname: Baumeier
authors.forename: Karl
authors.initials: K
authors.lastname: Leo
authors.forename: Moritz
authors.initials: M
authors.lastname: Riede
authors.forename: Peter
authors.initials: P
authors.lastname: Bäuerle
authors.forename: Denis
authors.initials: D
authors.lastname: Andrienko