A New Class of Cyclometalated Ruthenium Sensitizers of the Type ĈNN for Efficient Dye-Sensitized Solar Cells

A new class of cyclometalated ruthenium sensitizers incorporating a ĈNN ligand and conjugated 2,2'-bipyridine in the ancillary ligand have been designed and synthesized. The photovoltaic performance of JK-206 using an electrolyte containing 0.6 M 1,2-dimethyl-3-propylimidazolium iodide, 0.05 M I(2), 0.1 M LiI, and 0.5 M tert-butylpyridine in CH(3)CN gave a short-circuit photocurrent density of 19.63 mA cm(-2), an open-circuit voltage of 0.74 V, and a fill factor of 0.72, affording an overall conversion efficiency of 10.39%. The efficiency is the highest one reported for dye-sensitized solar cells based on the cyclometalated ruthenium sensitizer of the type ĈNN. Moreover, the same device using a polymer gel electrolyte exhibited a remarkable stability under 1000 h of light soaking at 60 °C, retaining 91% of the initial efficiency of 7.14%.