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On the Interface Dipole at the Pentacene-Fullerene Heterojunction: A Theoretical Study

Mathieu Linares, David Beljonne, Jérôme Cornil, Kelly Lancaster, Jean-Luc Brédas, Stijn Verlaak, Alexander Mityashin, Paul Heremans, Julien Idé, Raphaël Méreau, Philippe Aurel, Laurent Ducasse, Frédéric Castet, Washington (2010)

The electronic structure at organic/organic interfaces plays a key role, among others, in defining the quantum efficiency of organics-based photovoltaic cells. Here, we perform quantum-chemical and micro-electrostatic calculations on molecular aggregates of various sizes and shapes to characterize the interfacial dipole moment at pentacene/C60 heterojunctions. The results show that the interfacial dipole mostly originates in polarization effects due to the asymmetry in the multipolar expansion of the electronic density distribution between the interacting molecules, rather than in a charge transfer from donor to acceptor. The local dipole is found to fluctuate in sign and magnitude over the interface and appears as a sensitive probe of the relative arrangements of the pentacene and C60 molecules (and of the resulting local electrical fields sensed by the molecular units).

Partners : UMons, imec

Place of Publication : Washington

Date of Publication : 2010/02/02

Additional Data : JOURNAL OF PHYSICAL CHEMISTRY C, Volume: 114 Issue: 7

Link to the online version of the article.