Band structure engineering in organic semiconductors.
A key breakthrough in modern electronics was the introduction of band structure engineering, the design of almost arbitrary electronic potential structures by alloying different semiconductors to continuously tune the band gap and band-edge energies. Implementation of this approach in organic semiconductors has been hindered by strong localization of the electronic states in these materials. We show that the influence of so far largely ignored long-range Coulomb interactions provides a workaround. Photoelectron spectroscopy confirms that the ionization energies of crystalline organic semiconductors can be continuously tuned over a wide range by blending them with their halogenated derivatives. Correspondingly, the photovoltaic gap and open-circuit voltage of organic solar cells can be continuously tuned by the blending ratio of these donors.
Institut für Angewandte Photophysik, Technische Universität Dresden, 01069 Dresden, Germany.
Martin
M
Schwarze
Biomolecular and Organic Electronics, IFM, Linköping University, 58183 Linköping, Sweden.
Wolfgang
W
Tress
Fraunhofer Institute for Electron Beam, Plasma Technology and COMEDD, 01109 Dresden, Germany.
Beatrice
B
Beyer
Biomolecular and Organic Electronics, IFM, Linköping University, 58183 Linköping, Sweden.
Feng
F
Gao
Institut für Angewandte Photophysik, Technische Universität Dresden, 01069 Dresden, Germany. Dresden Center for Computational Materials Science, Technische Universität Dresden, 01062 Dresden, Germany.
Reinhard
R
Scholz
Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.
Carl
C
Poelking
Institut für Angewandte Photophysik, Technische Universität Dresden, 01069 Dresden, Germany.
Katrin
K
Ortstein
Institut für Angewandte Photophysik, Technische Universität Dresden, 01069 Dresden, Germany.
Alrun A
AA
Günther
Institut für Angewandte Photophysik, Technische Universität Dresden, 01069 Dresden, Germany.
Daniel
D
Kasemann
Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.
Denis
D
Andrienko
Institut für Angewandte Photophysik, Technische Universität Dresden, 01069 Dresden, Germany. leo@iapp.de.
Karl
K
Leo