Structure and photoelectrochemical properties of ruthenium(II) polypyridyl complexes as sensitizers for nanocrystalline TiO2 electrodes

The relationship between the structures and photoelectrochemical properties of two dyes, cis-dithiocyanato-N,N′-bis(4,4′-dicarboxyl-2,2′-bipyridyl) Ru(II) and cis-dithiocyanato-(4,4′-dicarboxyl-2,2′-bipyridyl)-(4,4′-di((N,N′-methylphenylamino)methylene)-2,2′-bipyridyl) Ru(II), was examined and compared under the same conditions. Data show that the photophysical properties (including molar extinction coefficients ε and excited-state lifetimes) and photoelectrochemical properties (including short-circuit photocurrent, open-circuit photovoltage, incident monochromatic photon to current conversion efficiency, overall energy conversion yield (η) and transient photocurrent) were changed greatly only due to an acceptor replaced by a donor in one of polypyridyl of the Ru(II) complex, suggesting that the molecular design in energy conversion is very sensitive.