Bis(1,1-bis(2-pyridyl)ethane)copper(/) as an efficient redox couple for liquid dye-sensitized solar cells

A new redox couple, [Cu(bpye) 2 ] +/2+ , has been synthesized, and applied in dye-sensitized solar cells (DSSCs). Overall efficiencies of 9.0% at 1 sun and 9.9% at 0.5 sun were obtained, which are considerably higher than those obtained for cells containing the reference redox couple, [Co(bpy) 3 ] 2+/3+ . These results represent a record for copper-based complex redox systems in liquid DSSCs. Fast dye regeneration, sluggish recombination loss processes, faster electron self-exchange reactions and suitable redox potentials are the main reasons for the observed increase in efficiency. In particular, the main disadvantage of cobalt complex-based redox couples, charge-transport problems, appears to be resolved by a change to copper complex redox couples. The results make copper complex-based redox couples very promising for further development of highly efficient DSSCs. A new redox couple, [Cu(bpye) 2 ] +/2+ , has been synthesized and applied in DSSCs. Overall efficiencies above 9.0% and good photostability were obtained. Excellent electrolyte charge transport, fast regeneration and low recombination are the major reasons for the high efficiencies.