title: Energy-level alignment at organic heterointerfaces.
abstract: Today's champion organic (opto-)electronic devices comprise an ever-increasing number of different organic-semiconductor layers. The functionality of these complex heterostructures largely derives from the relative alignment of the frontier molecular-orbital energies in each layer with respect to those in all others. Despite the technological relevance of the energy-level alignment at organic heterointerfaces, and despite continued scientific interest, a reliable model that can quantitatively predict the full range of phenomena observed at such interfaces is notably absent. We identify the limitations of previous attempts to formulate such a model and highlight inconsistencies in the interpretation of the experimental data they were based on. We then develop a theoretical framework, which we demonstrate to accurately reproduce experiment. Applying this theory, a comprehensive overview of all possible energy-level alignment scenarios that can be encountered at organic heterojunctions is finally given. These results will help focus future efforts on developing functional organic interfaces for superior device performance.
authors.affiliation: Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Bereich Solarenergieforschung, Albert-Einstein-Straße 15, 12489 Berlin, Germany. ; Institut für Physik, Humboldt-Universität zu Berlin, Newtonstraße 15, 12489 Berlin, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Oehzelt
authors.affiliation: Institut für Physik, Humboldt-Universität zu Berlin, Newtonstraße 15, 12489 Berlin, Germany.
authors.forename: Kouki
authors.initials: K
authors.lastname: Akaike
authors.affiliation: Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Bereich Solarenergieforschung, Albert-Einstein-Straße 15, 12489 Berlin, Germany. ; Institut für Physik, Humboldt-Universität zu Berlin, Newtonstraße 15, 12489 Berlin, Germany.
authors.forename: Norbert
authors.initials: N
authors.lastname: Koch
authors.affiliation: Institut für Physik, Humboldt-Universität zu Berlin, Newtonstraße 15, 12489 Berlin, Germany.
authors.forename: Georg
authors.initials: G
authors.lastname: Heimel
keywords: energy-level alignment; organic electronics; organic heterointerfaces; semi-clasical modeling