New Efficient Ruthenium Sensitizers with Unsymmetrical Indeno[1,2-b]thiophene or a Fused Dithiophene Ligand for Dye-Sensitized Solar Cells

Abstract

Two novel ruthenium sensitizers containing unsymmetrical indeno[1,2-1Athiophene or a fused dithiophene unit in the ancillary ligand have been designed and synthesized. The photovoltaic performance of JK-188 using an electrolyte consisting of 0.6 M 1,2-dimethy1-3-propylimidazolium iodide, 0.05 M12, 0.1 M Lil, 0.05 M guanidinium thiocyanate, and 0.5 M tert-butylpyridine in acetonitrile revealed a short-circuit photocurrent density of 18.60 mA/cm2, an open-circuit voltage of 0.72 V, and a fill factor of 0.71, yielding an overall conversion efficiency of 9.54%. The cell exhibits a remarkable stability under 1000 h of light soaking at 60 degrees C using a quasi-solid-state electrolyte consisting of 5 wt % poly(vinylidenefluoride-co-hexafluoropropylene), 0.6 M 1-propy1-2,3-dimethylimidazolium iodide, 0.5 M N-methylbenzimidazole, and 0.1 M 12 in 3-methoxypropionitrile, retaining 97% of the initial efficiency (7.38%).