10436
Macromolecules 2005, 38, 10436-10448
Synthesis of Conjugated Polymers Containing Terpyridine-Ruthenium Complexes: Photovoltaic Applications Virginie Duprez,* Matteo Biancardo, Holger Spanggaard, and Frederik C. Krebs The Danish Polymer Centre, RISØ National Laboratory, P.O. Box 49, DK-4000 Roskilde, Denmark Received June 17, 2005; Revised Manuscript Received October 3, 2005
ABSTRACT: We report the synthesis of (E)-3-(4-bromo-2,5-dioctylphenyl)-2-(4-vinylphenyl)acrylonitrile (5). We further report the synthesis of conjugated polymer materials by palladium-catalyzed Heck coupling polymerization of 5 and 4-bromo-2,5-dioctyl-4′-vinylstilbene (3) in the presence of 4′-(4-bromophenyl)2,2′:6′,2′′-terpyridine (8), giving poly(dioctylstilbenevinylene)s terminated by a terpyridine moiety. Their assembly using ruthenium complexation led to coordination homopolymers and copolymer with tetrafluoroborate counterions. The materials were characterized using SEC, MALDI, NMR, UV-vis, and fluorescence spectroscopy. The polymers were found to transfer energy to the complexes as seen through the complexes ability to quench fluorescence. The coordination polymers were applied to photovoltaics, and two types of devices were prepared: polymer solar cells obtained by spin-coating of the coordination polymer solution onto PEDOT:PSS-covered ITO substrates and dye-sensitized solar cells obtained by absorption on TiO2 nanocrystalline films using two different electrolytes. Dye-sensitized solar cells (DSSCs) prepared using the copolymer 15 gave the best results with efficiencies reaching ∼0.1% with the redox couple CoII,III as electrolyte, whereas the coordination homopolymer 13 gave the best results as organic solar cells with very low efficiency (
