Humboldt-Universit?t zu Berlin, Institut für Physik, Newtonstr. 15, 12489 Berlin, Germany
Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Bereich Solarenergieforschung, Albert-Einstein-Str. 15, 12489 Berlin, Germany
题目: Interface and bulk charge carrier density manipulation in organic semiconductors
Interfaces: Inducing Fermi-level pinning in an organic semiconductor at the interface to another material results in accumulation or depletion of electrons at the interface. For instance, band-bending at a pinned organic/electrode interface may result. The energy level alignment at organic/organic heterojunctions comprising donors and acceptors, as used in organic photovoltaic cells, is essentially independent of deposition sequence, as long as supporting electrodes do not induce energy level pinning. When the energy levels become Fermi-level pinned due to long-range charge transfer, an electric field may be induced right at, and beyond, the heterojunction. This effect is exemplified for prototypical donor and the acceptor interfaces, which are relevant for photovoltaic cells.
Bulk: Despite the pivotal role of controlled semiconductor doping for inorganic microelectronic devices, the majority of organic electronic devices is still based on intrinsic organic semiconductors. Current research efforts are, therefore, directed towards applying strong organic donor/acceptor molecules as dopants of organic semiconductors. Despite the success of this strategy in improving organic electronic device performance, persistent inconsistencies in current models for the fundamental mechanism of molecular electrical doping preclude further progress. On the basis of a combined experimental and theoretical study, a different model is developed that resolves most of these inconsistencies. Doping is rationalized through intermolecular hybridization of organic semiconductor and dopant frontier molecular orbitals, and design strategies for improved molecular dopants can be derived.
1997 Diploma in Physics at the Technical University Graz (Austria)
2000 PhD in Physics at the Technical University Graz (Austria)
2000-2002 Research Associate at Princeton University (USA)
2003-2004 Research Associate at Humboldt University Berlin (Germany)
2004-2009 Head of the Emmy Noether Independent Junior Research Group
"Supramolecular Systems" (DFG) at Humboldt University
since 2009 Full Professor at Humboldt University, Department of Physics