Synthesis, spectral, electrochemical and photovoltaic properties of novel heteroleptic polypyridyl ruthenium(II) donor-antenna dyes

Titelangaben

Gräf, Katja ; Fischer, Katja ; Kisselev, Roman ; Thelakkat, Mukundan:
Synthesis, spectral, electrochemical and photovoltaic properties of novel heteroleptic polypyridyl ruthenium(II) donor-antenna dyes.
In: Journal of Materials Chemistry. Bd. 19 (2009) Heft 30 . - S. 5364-5376.
ISSN 1364-5501
DOI: https://doi.org/10.1039/b901988j

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Abstract

A series of new heteroleptic Ru(II)(4,4-dicarboxylic acid-2,2-bipyridine)(bipyridyl donor-antenna ligand)(NCS)2 complexes carrying different donor-antenna moieties was designed, synthesised and characterised. A general synthetic procedure was used for the covalent attachment of the donor-antenna units 1,3-di(2-thienyl)benzo[c]-thiophene (DTBT), trans-stilbene (tS) and 4-{2-[2-(2-methoxyethoxy)ethoxy]-ethoxy}-N,N-diphenylbenzenamine (TPA-EO) to 2,2-bipyridine. First, a Vilsmeier-Haack reaction was applied to get the respective aldehyde-functionalised donor-antenna compounds which secondly reacted with 4,4-bis(triphenylphosphonium-methyl)-2,2-bipyridyl chloride under Wittig conditions to give the desired bipyridyl donor-antenna molecules. To create a dimethylamino (NMe2) substituted donor-antenna compound a reaction between 4,4-dimethyl-2,2-bipyridine and Bredereck's reagent was carried out. The final Ru(II) complexes referred to as Ru-DTBT-NCS, Ru-tS-NCS, Ru-TPA-EO-NCS and Ru-NMe2-NCS were obtained via one-pot reactions, starting from dichloro(p-cymene)ruthenium(II) dimer. The bipyridyl donor-antenna molecules as well as the complexes were fully characterised and their optical and electrochemical properties were studied in detail. Preliminary tests of the novel Ru(II)bis(bipyridyl)(NCS)2 dyes in solid-state dye-sensitized solar cells under AM1.5G conditions (100 mW cm-2) yielded short-circuit current densities of 1.06, 2.15, 3.42 and 4.03 mA cm-2, open-circuit voltages of 625, 635, 685 and 735 mV and fill factors of about 45% corresponding to overall efficiencies of 0.31, 0.58, 0.99 and 1.37% for Ru-DTBT-NCS, Ru-NMe2-NCS, Ru-tS-NCS and Ru-TPA-EO-NCS, respectively.