On the Interface Dipole at the Pentacene-Fullerene Heterojunction: A Theoretical Study
Linares, Mathieu × Beljonne, David Cornil, Jerome Lancaster, Kelly Bredas, Jean-Luc Verlaak, Stijn Mityashin, Alexander Heremans, Paul Fuchs, Andreas Lennartz, Christian Ide, Julien Mereau, Raphael Aurel, Philippe Ducasse, Laurent Castet, Frederic #
American Chemical Society
Journal of Physical Chemistry C vol:114 issue:7 pages:3215-3224
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 microelectrostatic calculations oil molecular aggregates of various sizes and shapes to characterize the interfacial dipole moment at pentacene/C-60 heterojunctions. The results show that the interfacial dipole mostly originates in polarization effects Clue 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 ill Sign and Magnitude over the interface and appears as a sensitive probe of the relative arrangements of the pentacene and C-60 molecules (and of the resulting local electrical fields sensed by the molecular units).