Regensburg 2013 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 65: Poster: Organic electronics and photovoltaics (CPP; jointly with HL, O)
HL 65.9: Poster
Wednesday, March 13, 2013, 16:30–18:30, Poster C
Influence of different alkyl side chains on merocyanine dye performance in organic solar cells — •Julian Krumrain1, Alhama Arjona Esteban2, Steven Graf1, Martin Lenze1, Dirk Hertel1, Frank Würthner2, and Klaus Meerholz1 — 1Department für Chemie, Universität zu Köln, Luxemburger Straße 116, 50939 Köln (Germany) — 2Institut für Organische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg (Germany)
In recent years, organic photovoltaics have attracted great attention as an alternative energy source due to their reduced cost and easier proccessibility, compared to inorganic materials. Specifically, small-molecule dyes have achieved great strides in recent years reaching power conversion efficiencies up to 7%. These dyes have advantages over polymers, most notably their simplified, large-scale syntheses and purification. Furthermore small molecules can be processed either by solution or vapor-deposition processes. We have investigated organic solar cells based on merocyanine (MC) dyes as an electron donor material in vacuum-deposition processed bulk-heterojunctions (BHJ). In order to get a better understanding of the influence of side chains on the MC dyes in BHJ, we have synthesized MC dyes with different alkyl side chain lengths. We have carried out temperature and light intensity dependent current-voltage measurements as well as atomic force microscopy studies. It becomes apparent that the BHJ morphology is strongly influenced by the side chain length. The short-circuit current density degreases enormously for increasing side chain length in complete contrast to the solubility of the MC dyes.