Cyclopentadithiophene Bridged Donor-Acceptor Dyes Achieve High Power Conversion Efficiencies in Dye-Sensitized Solar Cells Based on the tris-Cobalt Bipyridine Redox Couple

Good Co‐op: A novel cyclopentadithiophene‐bridged donor–acceptor dye applied as sensitizer in mesoscopic dye‐sensitized solar cells, in conjunction with the cobalt complexes [CoII(bpy)3](B(CN)4)2 and [CoIII(bpy)3](B(CN)4)3 as redox couple, yields high power conversion efficiencies (up to 9.6 %) under standard AM 1.5G solar irradiation. The results confirm that cobalt complexes are legitimate alternatives to the commonly used I−/I3− redox shuttle when used with judiciously engineered organic sensitizers.