Regensburg 2010 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 48: [O] Organic Electronics and Photovoltaics III (Joint Session DS/CPP/HL/O)
DS 48.2: Vortrag
Freitag, 26. März 2010, 11:30–11:45, H40
Mixed Self-Assembled Monolayers on Au(111): Understanding the Level Alignment and Work-Function Modification. — •Ferdinand Rissner1, David A. Egger1, Lorenz Romaner2, Georg Heimel3, and Egbert Zojer1 — 1Institute of Solid State Physics, Graz University of Technology, Austria — 2Chair of Atomistic Modelling and Design of Materials, University of Leoben, Austria — 3Institut für Physik, Humboldt-Universität zu Berlin, Germany
In organic electronics, coverage of electrodes with appropriate self-assembled monolayers (SAMs) is a well-known technique for enhancing the performance of devices; by modification of the electrode work function, Φ, charge-carrier injection barriers can be optimized. Mixing molecules which show a work-function increasing effect (ΔΦ>0) with molecules decreasing Φ was experimentally found to allow for tuning of Φ over a wide range (as a function of the mixing ratio). [1]
For “pure” SAMs of π-conjugated oligophenylene derivatives, the mechanisms controlling the metal/SAM interface energetics have been extensively investigated over the past years. Here, we present density-functional theory based slab-type band structure calculations on the energetics of mixed monolayers. We find and explain significant differences in the energy-level alignment compared to what is known from the respective pure layers.
[1] K.-Y. Wu, S.-Y. Yu and Y.-T. Tao, Langmuir, 2009, 25 (11), pp 6232-6238.