A new ruthenium sensitizer containing dipyridylamine ligand for effective nanocrystalline dye-sensitized solar cells

Two series of novel ruthenium bipyridyl sensitizers incorporating conjugated dipyridylamine ligands with general formula [Ru (dcbpy) (L) (NCS)2, where dcbpy is 4,4′-dicarboxylic acid-2,2′-bipyridine and L is N-hexyl-4,4′-di(4-hexylstyryl)-2,2′-dipyridylamine, JJ-95 or N-hexyl-4,4′-di{(5-hexylthiophen-2-yl)vinyl}-2,2′-dipyridylamine, JJ-99] have been synthesized and demonstrated as efficient sensitizers in dye-sensitized solar cells. A mesoporous titania film stained with JJ-99 exhibits a remarkable incident monochromatic photon-to-current conversion efficiency of 84%. Under standard AM 1.5 sunlight, the solar cell using a liquid-based electrolyte exhibits a short-circuit photocurrent density of 18.89 mA/cm2, an open-circuit voltage of 0.66 V, and a fill factor of 0.69, corresponding to an overall conversion efficiency of 8.76%.