Dresden 2003 – wissenschaftliches Programm
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CPP: Chemische Physik und Polymerphysik
CPP 8: Neue Methoden
CPP 8.4: Vortrag
Mittwoch, 26. März 2003, 17:45–18:00, ZEU/160
Organic Microcavity Photodiodes: Tailoring The Photocurrent Response — •Robert Koeppe1, Jürgen G. Müller1, Uli Lemmer1,2, John M. Lupton1, Jochen Feldmann1, and Ullrich Scherf3 — 1Sektion Physik, LMU München — 2Universität Karlsruhe — 3Universität Wuppertal
Organic photodiodes made of conjugated polymers show many promising features for future applications. We use a bilayer structure comprising a conjugated polymer and a fullerene electron acceptor sandwiched between electrodes that also act as semitransparent mirrors, forming an organic microcavity photodiode.
Photocurrent spectra of these devices show a sharp peak at the microcavity resonance in a spectral region of very low absorption in the polymer layer. We attribute this additional photocurrent to the resonant cavity enhanced absorption in the diode. The spectrally narrow enhancement of the photocurrent in the microcavity may lead to applications like simple spectrometer devices or provide improved spectral response in organic solar cells.
Additionally, we observe an enhancement of two-photon induced photocurrent by a factor of over 500 in our organic microcavity photodiodes. This is also due to the cavity induced field increase which leads to a higher probability for nonlinear processes. We demonstrate a simple autocorrelator setup using an organic microcavity photodiode as the only nonlinear optical element.