In the field of organic electronics, a central issue is to assess how the frontier electronic levels of two adjacent organic layers align with respect to one another at the interface. This alignment can be driven by the presence of a partial charge transfer and the formation of an interface dipole; it plays a key role for instance in determining the rates of exciton dissociation or exciton formation in organic solar cells or light-emitting diodes, respectively. Reliably modeling the processes taking place at these interfaces remains a challenge for the computational chemistry community. Here, we review our recent theoretical work on the influence of the choice of density functional theory (DFT) methodology on the description of the charge-transfer character in the ground state of TTF/ TCNQ model complexes and interfaces. Starting with the electronic properties of the isolated TTF and TCNQ molecules and then considering the charge transfer and resulting interface dipole in TTF/TCNQ donor-acceptor stacks and bilayers, we examine the impact of the choice of DFT functional in describing the interfacial electronic structure. Finally, we employ computations based on periodic boundary conditions to highlight the impact of depolarization effects on the interfacial dipole moment.
Bibliographical noteFunding Information:
The authors acknowledge the European project MINOTOR (FP7-NMP-228424) for financial support. The work in Mons is also partly supported by the Interuniversity Attraction Pole IAP 6/27 of the Belgian Federal Government and by the Belgian National Fund for Scientific Research (FNRS/FRFC). J.C. and D.B. are FNRS Research Fellows. The work at Georgia Tech has been partly supported by the Center for Advanced Molecular Photovoltaics, Award No. KUS-C1-015-21, made by King Abdullah University of Science and Technology (KAUST); the Georgia Research Alliance; and the STC Program of the National Science Foundation under Award DMR-0120967.
- Interface dipole
- Organic electronics
- Partial charge transfer
ASJC Scopus subject areas
- Physical and Theoretical Chemistry