Regensburg 2010 – scientific programme
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O: Fachverband Oberflächenphysik
O 29: [CPP] Organic Electronics and Photovoltaics I (Joint Session DS/CPP/HL/O)
O 29.5: Talk
Tuesday, March 23, 2010, 10:30–10:45, H37
Dicyanovinyl sexithiophenes: self-organization and photovoltaic properties — •Marieta Levichkova1, David Wynands1, Alexandr Levin1, Karl Leo1, Karsten Walzer2, Dirk Hildebrandt2, Peter Bäuerle3, Rosina Rentenberger4, and Moritz Riede1 — 1Institut für Angewandte Photophysik, TU Dresden, Germany — 2Heliatek GmbH, Dresden, Germany — 3Institut für Organische Chemie II und Neue Materialien, Universität Ulm, Germany — 4Institut für Physik, TU Ilmenau, Germany
Recently, vacuum deposited films consisting of conjugated dicyanovinyl-capped (DCV) oligothiophenes have shown significant potential as photoactive layers in small molecule solar cells [1]. Here, we study the structural and optical properties of films of two DCV-derivatives both comprising six thiophene rings (DCV6Ts) but having different side groups. For both derivatives, neat DCV6T and mixed DCV6T:C60 films are compared using UV-VIS absorption and photoluminescence spectroscopy, X-ray diffraction (XRD), and Atomic Force Microscopy. It is shown that the modification of the molecular structure results in a structured and red shifted absorption band, which indicates better molecular arrangement in the solid state. The improved self-organization at room temperature deposition is confirmed by XRD. Furthermore, the nanomorphology of the mixed DCV6T:C60 films is optimized using substrate heating. Bulk heterojunction solar cells with power conversion efficiencies exceeding 4% are presented.
[1] K. Schulze et al., Adv. Mater. 2006, 18, 2872-2875