Dresden 2009 – scientific programme

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SYOP: Symposium Organic Photovoltaics: From Single Molecules to Devices

SYOP 4: Organic Photovoltaics: from Single Molecules to Devices

SYOP 4.13: Poster

Thursday, March 26, 2009, 16:30–19:00, P1A

Investigation of the Nanomorphology and Device Performance of Organic Solar Cells based on Polymer:Fullerene Bulk Heterojunctions — •Thomas Madena, Uli Wischnath, Achim Kittel, Jürgen Parisi, and Ingo Riedel — Energy- and Semiconductor Research Laboratory, Department of Physics, University of Oldenburg, Carl-von-Ossietzky-Strasse 9-11, D-26111 Oldenburg

The coherences between structural layout of P3HT:PCBM bulk heterojunction (BHJ) solar cells and the electrical properties are not fully understood so far. The morphology of such BHJ-thin films determines the efficiency balance between separation of electron hole pairs at the phase boundary of PCBM and P3HT and the charge transport along continuous paths in the pure materials. The optimization of both fundamental mechanisms is a challenge and plays a crucial role for the efficiency of the photovoltaic device. In this presentation we investigate the interplay of nanomorphology and device properties of P3HT: PCBM solar cells. AFM measurements were carried out to profile the nanomorphology of differently composed polymer: fullerene composite films. In these films we observed substantial growth of micron-sized crystallites in the PCBM moiety upon thermal annealing which severely limits the device performance. Based on these studies we discuss the influence of the nanomorphology of different thin film formulations on the electrical characteristics of P3HT: PCBM solar cells.