Year: 2019
Type: article
Abstract: The functionality of organic semiconductor devices crucially depends on molecular energies, namely the ionisation energy and the electron affinity. Ionisation energy and electron affinity values of thin films are, however, sensitive to film morphology and composition, making their prediction challenging. In a combined experimental and simulation study on zinc-phthalocyanine and its fluorinated derivatives, we show that changes in ionisation energy as a function of molecular orientation in neat films or mixing ratio in blends are proportional to the molecular quadrupole component along the π-π-stacking direction. We apply these findings to organic solar cells and demonstrate how the electrostatic interactions can be tuned to optimise the energy of the charge-transfer state at the donor-acceptor interface and the dissociation barrier for free charge carrier generation. The confirmation of the correlation between interfacial energies and quadrupole moments for other materials indicates its relevance for small molecules and polymers.
Source: Nature Communications
Authors: Martin Schwarze, Karl Sebastian Schellhammer, Katrin Ortstein, Johannes Benduhn, Christopher Gaul, Alexander Hinderhofer, Lorena Perdigón Toro, Reinhard Scholz, Jonas Kublitski, Steffen Roland, Matthias Lau, Carl Poelking, Denis Andrienko, Gianaurelio Cuniberti, Frank Schreiber, Dieter Neher, Koen Vandewal, Frank Ortmann, Karl Leo
Institutions: Dresden Integrated Center for Applied Physics and Photonic Materials, Technische Universität Dresden, Max Bergmann Center of Biomaterials, Center for Advancing Electronics Dresden, Dresden Center for Computational Materials Science, University of Tübingen, University of Potsdam, Max Planck Institute for Polymer Research, Hasselt University
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,376
Funders: Canadian Institute for Advanced Research, Doctors Company Foundation, European Commission, Deutsche Forschungsgemeinschaft, European Synchrotron Radiation Facility, Bundesministerium für Bildung und Forschung, Technische Universität Dresden, Sächsische Landesbibliothek – Staats- und Universitätsbibliothek Dresden, Horizon 2020 Framework Programme
OpenAlex ID: W2948675137