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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 24: Organic Semiconductors

CPP 24.7: Vortrag

Mittwoch, 13. März 2013, 11:30–11:45, H40

Molecular Ordering and Charge-Transport Properties of Semi-Crystalline Conjugated Polymers via Computer Simulations — •Carl Poelking¹, Eunkyung Cho², Alexander Malafeev³, Viktor Ivanov³, Kurt Kremer¹, Chad Risko², Jean-Luc Bredas², and Denis Andrienko¹ — ¹Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany — ²Center for Organic Photonics and Electronics, Georgia Institute of Technology, Atlanta, USA — ³Physics Department, Moscow State University, Moscow, Russia

We establish a link between the microscopic ordering, charge-transport parameters and carrier mobilities for semi-crystalline polymeric semiconductors using a computational multiscale approach. As material examples, we investigate poly(bithiophene-alt-thienothiophene) (PBTTT) and the polymorphic poly(3-hexyl-thiophene) (P3HT). We identify the structural origin of the regioregularity effect on mobility as a broadened energetic density of states and resolve how the packing of side chains, ranging from highly crystalline to amorphous, affects dynamics and distributions of site energies and electronic couplings via orthogonal modes of the backbone paracrystallinity. Simulated hole mobilities are in excellent agreement with experimental values for organic field-effect transistors. The results underline that to secure efficient charge transport in conjugated polymers, (i) electronic couplings should present fast dynamics next to high average values, and (ii) backbone paracrystallinity (intimately related with energetic disorder) should be small.