Berlin 2005 – wissenschaftliches Programm

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DS: Dünne Schichten

DS 24: Postersitzung II

DS 24.13: Poster

Dienstag, 8. März 2005, 17:00–19:00, Poster TU B

Characterization of ruthenium dyes for organic solar cells with Raman and SERS micro-spectroscopy — •Carmen Pérez León¹, Lothar Kador¹, Bin Peng², and Mukundan Thelakkat² — ¹University of Bayreuth, Institute of Physics and Bayreuther Institut für Makromolekülforschung (BIMF), 95440 Bayreuth — ²University of Bayreuth, Macromolecular Chemistry I, 95440 Bayreuth

Ruthenium(II) complexes containing polypyridyl ligands have been widely studied as potential photosensitizers in organic solar cells. Of particular interest is their use in dye-sensitized solar cells based on nanocrystalline films of TiO₂. We have investigated the new dye Ru-TPA₂ with amino ligands and the well-known N719 complex with thiocyanate moieties. The influence of the solvent on the adsorption of the complexes on colloidal nanoparticles and their spectroscopic properties have been studied. The electronic transitions of both dyes show solvatochromic shifts due to specific interactions of the ligands with the solvent molecules. The surface-enhanced Raman (SER) spectra of the dyes dissolved in water, ethanol, and acetonitrile were measured in silver and gold colloidal solutions. The results show that the dyes are adsorbed on the metallic nanoparticles in different ways for different solvents. Deprotonation, H-bonding, and donor-acceptor interactions seem to determine these different behaviors. Furthermore, experiments in which the dyes are adsorbed on TiO₂ were also performed, showing characteristics of the binding of the sensitizers to the semiconductor surface.