Berlin 2008 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 22: Hybrid systems
HL 22.5: Vortrag
Dienstag, 26. Februar 2008, 10:30–10:45, EW 201
Light-Induced Charge Transfer in Hybrid Composites of Silicon Nanocrystals and Organic Semiconductors — •Roland Dietmüller1, Sabrina Niesar1, Robert Lechner1, André R. Stegner1, Rui N. Pereira1, Martin S. Brandt1, Martin Trocha2, Hartmut Wiggers3, and Martin Stutzmann1 — 1Walter Schottky Institut, Technische Universität München, Am Coulombwall 3, 85748 Garching, Germany — 2Evonik Degussa GmbH, Paul-Baumann-Str.1, 45772 Marl, Germany — 3Institut für Verbrennung und Gasdynamik, Universität Duisburg-Essen, Lotharstr. 1, 47048 Duisburg, Germany
Organic semiconductors have received a lot of attention for novel, low cost electronic applications. Silicon or SiGe nanocrystals could be incorporated in such organic devices to tailor their physical properties. For example, hybrid organic/inorganic solar cells could benefit from the solution processing of the organic and inorganic components and from the broad absorption range of the non-toxic silicon.
We have investigated the charge transfer between Silicon nanocrystals (Si-nc) and organic semiconductors via light-induced electron spin resonance (LESR). Composites of Si-nc with the π-conjugated polymer poly(3-hexylthiophene-2,5-diyl) (P3HT) and with the fullerene derivate [6,6]-phenyl C-61-butyric acid methyl ester (PCBM) have been probed with LESR. The LESR measurements show that a light-induced charge transfer between Si-nc and P3HT takes place, which results in a positive polaron on the P3HT. PCBM, in contrast, acts in composites with Si-nc as an electron acceptor and after illumination a long-living radical anion of PCBM can be detected.