title: Ordering of PCDTBT revealed by time-resolved electron paramagnetic resonance spectroscopy of its triplet excitons.
abstract: Time-resolved electron paramagnetic resonance (TREPR) spectroscopy is shown to be a powerful tool to characterize triplet excitons of conjugated polymers. The resulting spectra are highly sensitive to the orientation of the molecule. In thin films cast on PET film, the molecules' orientation with respect to the surface plane can be determined, providing access to sample morphology on a microscopic scale. Surprisingly, the conjugated polymer investigated here, a promising material for organic photovoltaics, exhibits ordering even in bulk samples. Orientation effects may significantly influence the efficiency of solar cells, thus rendering proper control of sample morphology highly important.
authors.affiliation: Institut für Physikalische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstrasse 21, 79104 Freiburg (Germany). Till.Biskup@physchem.uni-freiburg.de.|Freiburg Institute for Advanced Studies (FRIAS), Albert-Ludwigs-Universität Freiburg, Albertstrasse 19, 79104 Freiburg (Germany). Till.Biskup@physchem.uni-freiburg.de.
authors.forename: Till
authors.initials: T
authors.lastname: Biskup
authors.affiliation: Institut für Makromolekulare Chemie, Albert-Ludwigs-Universität Freiburg, Stefan-Meier-Strasse 31, 79104 Freiburg (Germany).
authors.forename: Michael
authors.initials: M
authors.lastname: Sommer
authors.affiliation: Institut für Physikalische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstrasse 21, 79104 Freiburg (Germany).
authors.forename: Stephan
authors.initials: S
authors.lastname: Rein
authors.affiliation: Institut für Physikalische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstrasse 21, 79104 Freiburg (Germany).
authors.forename: Deborah L
authors.initials: DL
authors.lastname: Meyer
authors.affiliation: Freiburger Materialforschungszentrum (FMF), Albert-Ludwigs-Universität Freiburg, Stefan-Meier-Strasse 21, 79104 Freiburg (Germany).|Fraunhofer-Institut für Solare Energiesysteme (ISE), Heidenhofstrasse 2, 79110 Freiburg (Germany).
authors.forename: Markus
authors.initials: M
authors.lastname: Kohlstädt
authors.affiliation: Freiburger Materialforschungszentrum (FMF), Albert-Ludwigs-Universität Freiburg, Stefan-Meier-Strasse 21, 79104 Freiburg (Germany).|Fraunhofer-Institut für Solare Energiesysteme (ISE), Heidenhofstrasse 2, 79110 Freiburg (Germany).
authors.forename: Uli
authors.initials: U
authors.lastname: Würfel
authors.affiliation: Institut für Physikalische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstrasse 21, 79104 Freiburg (Germany).|Freiburg Institute for Advanced Studies (FRIAS), Albert-Ludwigs-Universität Freiburg, Albertstrasse 19, 79104 Freiburg (Germany).
authors.forename: Stefan
authors.initials: S
authors.lastname: Weber
keywords: PCDTBT; TREPR; ordering; organic solar cells; triplet exciton