Ordering of PCDTBT Revealed by Time‐Resolved Electron Paramagnetic Resonance Spectroscopy of Its Triplet Excitons |
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Authors: | Dr. Till Biskup Dr. Michael Sommer Stephan Rein Deborah L. Meyer Dr. Markus Kohlstädt Dr. Uli Würfel Prof. Dr. Stefan Weber |
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Affiliation: | 1. Institut für Physikalische Chemie, Albert‐Ludwigs‐Universit?t Freiburg, Albertstrasse 21, 79104 Freiburg (Germany);2. Freiburg Institute for Advanced Studies (FRIAS), Albert‐Ludwigs‐Universit?t Freiburg, Albertstrasse 19, 79104 Freiburg (Germany);3. Institut für Makromolekulare Chemie, Albert‐Ludwigs‐Universit?t Freiburg, Stefan‐Meier‐Strasse 31, 79104 Freiburg (Germany);4. Freiburger Materialforschungszentrum (FMF), Albert‐Ludwigs‐Universit?t Freiburg, Stefan‐Meier‐Strasse 21, 79104 Freiburg (Germany);5. Fraunhofer‐Institut für Solare Energiesysteme (ISE), Heidenhofstrasse 2, 79110 Freiburg (Germany) |
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Abstract: | Time‐resolved electron paramagnetic resonance (TREPR) spectroscopy is shown to be a powerful tool to characterize triplet excitons of conjugated polymers. The resulting spectra are highly sensitive to the orientation of the molecule. In thin films cast on PET film, the molecules’ orientation with respect to the surface plane can be determined, providing access to sample morphology on a microscopic scale. Surprisingly, the conjugated polymer investigated here, a promising material for organic photovoltaics, exhibits ordering even in bulk samples. Orientation effects may significantly influence the efficiency of solar cells, thus rendering proper control of sample morphology highly important. |
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Keywords: | ordering organic solar cells PCDTBT TREPR triplet exciton |
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