Regensburg 2013 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 10: Poster: Charge transfer effects in molecular materials (related to symposium SYCT)

CPP 10.3: Poster

Monday, March 11, 2013, 17:30–19:30, Poster C

Effect of Polymorphism, Regioregularity and Paracrystallinity on Charge Transport in Poly(3-Hexyl-Thiophene) [P3HT] Nanofibers — •Carl Poelking, Kurt Kremer, and Denis Andrienko — Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany

We establish the link between molecular order and charge-transport parameters in poly(3-hexyl-thiophene) (P3HT) accounting for different polymorphic structures and regioregularities. Using atomistic molecular dynamics, we study structural transitions related to side-chain melting and a conversion from a non-interdigitated metastable (form I’) to the stable (form I) P3HT polymorph, as also observed experimentally, thus providing structural models for side-chain arrangement and backbone-backbone stacking. We investigate how packing modes and regioregularity effect paracrystalline and side-chain order and analyse effects thereof on the dynamics and distribution of electronic couplings and site energies. In particular, we demonstrate how a small concentration of defects in side-chain attachment can lead to a dramatic decrease in charge-carrier mobility due to a strong intermolecular contribution to the energetic disorder, which we attribute to fluctuations in backbone-backbone distances. Our simulated mobilities indicate excellent agreement with experimental values obtained for P3HT nanofibers.