RESUMO
A luminescent cationic iridium complex with a 2,2'-biimidazole ligand forms hydrogen-bonded 1 : 1 adducts with benzoate anions; photoexcitation of the metal complex in presence of 3,5-dinitrobenzoate triggers a proton-coupled electron transfer.
Assuntos
Luminescência , Prótons , Ânions/química , Benzoatos/química , Cátions/química , Cátions/efeitos da radiação , Cristalografia por Raios X , Transporte de Elétrons , Ligação de Hidrogênio , Imidazóis/química , Imidazóis/efeitos da radiação , Irídio/química , Irídio/efeitos da radiação , Ligantes , Luz , Modelos Biológicos , Modelos Moleculares , Estrutura Molecular , Compostos Organometálicos/química , Compostos Organometálicos/efeitos da radiação , FotoquímicaRESUMO
We report on the synthesis and characterization of a donor-acceptor ruthenium polypyridyl complex as a photosensitizer for p-type dye-sensitized solar cells (DSSCs). The electrochemical, photophysical, and photovoltaic performance of two ruthenium-based photosensitizers were tested in NiO-based DSSCs; bis-(2,2'-bipyridine-4,4'-dicarboxylic acid)(2)N-(1,10-phenanthroline)-4-nitronaphthalene-1,8-dicarboximide ruthenium(II), ([Ru(dcb)(2)(NMI-phen)](PF(6))(2)) and tris-(2,2'-bipyridine-4,4'-dicarboxylic acid)(3) ruthenium(ii), [(Ru(dcb)(3))Cl(2)]. The presence of an electron-accepting group, 4-nitronaphthalene-1,8-dicarboximide (NMI), attached to the phenanthroline of [Ru(dcb)(2)(NMI-phen)](2+) resulted in long-lived charge separation between reduced [Ru(dcb)(2)(NMI-phen)](2+) and NiO valence band holes; 10-50 µs. In the reduced state for [Ru(dcb)(2)(NMI-phen)](2+), the electron localized on the distal NMI group. In tests with I(3)(-)/I(-) and Co(4,4'-di-tert-butyl-bipyridine)(3)(2+/3+) electrolytes, [Ru(dcb)(2)(NMI-phen)](2+) outperformed [Ru(dcb)(3)](2+) in solar cell efficiency in devices. A record APCE (25%) was achieved for a ruthenium photosensitizer in a p-type DSSC. Insights on photosensitizer regeneration kinetics are included.