Berlin 2008 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 36: Poster III
HL 36.20: Poster
Mittwoch, 27. Februar 2008, 16:30–19:00, Poster D
Transport in Organic Solar Cells studied with Pulsed Electrically Detected Magnetic Resonance — Jan Behrends1, •Alexander Schnegg1, Elizabeth A. Thomsen2, Ifor D.W. Samuel2, David J. Keeble3, and Klaus Lips1 — 1Abt. Silizium-Photovoltaik, Hahn-Meitner-Institut Berlin, Berlin, Germany — 2Organic Semiconductor Centre, School of Physics & Astronomy, University of St Andrews, St Andrews, UK — 3Carnegie Laboratory of Physics, School of Engineering, Physics, and Mathematics, University of Dundee, Dundee, UK
We report about first pulsed electrically detected magnetic resonance (pEDMR) measurements on organic solar cells at room temperature. Samples containing a blend of MEH-PPV and PCBM were investigated by pEDMR both in spectral as well as in time domain in order to extract information about the electron spin states influencing the current through the device. The pEDMR spectrum gave rise to a single resonance line centered at g = 2.0028(5) which coincides with a polaron signal recently assigned by continuous wave EDMR. By measuring Rabi oscillations as a function of the spectral position in the pEDMR spectrum, we were able to exploit the unique capabilities of pEDMR to assign current determining spin states not only by their spectral position, but also by their interspin couplings. Plotting the Rabi frequencies as a function of the resonance field, two frequencies could be clearly separated, which resembles the case of two coupled electron spins.