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CPP: Chemische Physik und Polymerphysik

CPP 23: POSTER Functional Organic Thin Films

CPP 23.48: Poster

Thursday, March 30, 2006, 17:00–19:00, P2

Photoinduced Charge Transfer versus Triplet Exciton Formation in Polymer-Fullerene Composites: Consequences for Photovoltaic Performance — •Johannes Sieger¹, Carsten Deibel¹, Vladimir Dyakonov¹, Ingo Riedel², and Michael Pientka³ — ¹Experimental Physics VI, Physical Institute, University of Würzburg, 97074 Würzburg, Germany — ²Bavarian Centre for Applied Energy Research (ZAE Bayern), Am Hubland, 97074 Würzburg, Germany — ³Energy and Semiconductor Research, Department of Physics, University of Oldenburg, 26129 Oldenburg, Germany

The conjugated polymer OC1C10-PPV blended with the electron accepting fullerene derivative PCBM is a material system which had a strong impact on the development of organic photovoltaics. Searching for alternative acceptor materials, the attention has recently been drawn to a class of dimethanofullerenes, which are fullerene derivatives with a higher solubility and a well established chemistry enabling structural modification of the side groups in a desired way. By replacing the PCBM with 1,1-bis(4,4-dodecyloxyphenyl)-(5,6)C61 (DPM-12), a high open-circuit voltage (close to 1 V) combined with a rather low photocurrent was obtained in DPM-12 based devices. In order to explain the phenomena observed, i.e., the formation of triplet excitons in the solar cell absorber containing DPM-12, systematic studies using light induced electron spin resonance and photoluminescence detected magnetic resonance were applied. For proving the triplet nature of the new photoinduced absorption band, a spin sensitive technique called photoinduced absorption detected magnetic resonance was used.