Katrin Ortstein^1*, Sebastian Hutsch², Mike Hambsch^2,3, Kristofer Tvingstedt⁴, Berthold Wegner⁵, Johannes Benduhn¹, Jonas Kublitski¹, Martin Schwarze¹, Sebastian Schellhammer², Felix Talnack^2,3, Astrid Vogt⁶, Peter Bäuerle⁶, Norbert Koch⁵, Stefan C. B. Mannsfeld^2,3, Hans Kleemann¹, Frank Ortmann^2,7*, Karl Leo^2*

1 Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP) and Institute for Applied Physics, Technische Universität Dresden, 01062 Dresden, Germany

2 Center for Advancing Electronics Dresden, Technische Universität Dresden, 01062 Dresden, Germany

3 Faculty of Electrical and Computer Engineering, Technische Universität Dresden, 01062 Dresden, Germany

4 Lehrstuhl für Experimentelle Physik IV, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany

5 Institut für Physik & IRIS Adlershof, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 6, 12489 Berlin, Germany

6 Institut für Organische Chemie II und Neue Materialien, Universität Ulm, Albert-Einstein-Allee 11, 89081 Ulm, Germany

7 Technische Universität München, Department of Chemistry, Lichtenbergstr. 4, 85748 Garching

* Corresponding authors emails: katrin.ortstein@tu-dresden.de, frank.ortmann@tum.de, karl.leo@tu-dresden.de

DOI10.24435/materialscloud:g3-cp [version v1]

Publication date: Apr 28, 2021

How to cite this record

Katrin Ortstein, Sebastian Hutsch, Mike Hambsch, Kristofer Tvingstedt, Berthold Wegner, Johannes Benduhn, Jonas Kublitski, Martin Schwarze, Sebastian Schellhammer, Felix Talnack, Astrid Vogt, Peter Bäuerle, Norbert Koch, Stefan C. B. Mannsfeld, Hans Kleemann, Frank Ortmann, Karl Leo, Band gap engineering in blended organic semiconductor films based on dielectric interactions, Materials Cloud Archive 2021.66 (2021), doi: 10.24435/materialscloud:g3-cp.

Description

Blending organic molecules to tune their energy levels is currently investigated as an approach to engineer the bulk and interfacial optoelectronic properties of organic semiconductors. It has been proven that the ionization energy (IE) and electron affinity (EA) can be equally shifted in the same direction by electrostatic effects controlled by blending similar halogenated derivatives with different energetics. Here, we show that the energy gap of organic semiconductors can be tuned by blending as well. We use oligothiophenes with different numbers of thiophene rings as example and investigate their structure and electronic properties. Photoelectron spectroscopy and inverse photoelectron spectroscopy show tunability of the single-particle gap, with the optical gaps showing similar, but smaller effects. Theoretical analysis shows that this tuning is mainly caused by a change in the dielectric constant with blend ratio. Further studies will explore the practical impact of this energy-level engineering strategy in optoelectronic devices.

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Keywords

energy level tuning photoelectron spectroscopy dielectric interactions theoretical simulations