Towards efficient sustainable full-copper dye-sensitized solar cells.

Two new heteroleptic copper(i) sensitizers bearing 6,6 '-dimethyl-2,2 '-bipyridine-4,4 '-dibenzoic acid, to anchor the dye on the titania surface, and a pi-delocalized 2-(R-phenyl)-1H-phenanthro[9,10-d]imidazole (R = NPh2 or O-hexyl) ancillary ligand were prepared and well characterized. Their performance as dyes in DSSCs is quite similar to that of the related complex bearing 2,9-dimesityl-1,10-phenanthroline as an ancillary ligand, when using the common I-/I-3(-) redox couple or homoleptic copper complexes as electron shuttles. The experimental results along with theoretical calculations confirm the great potential of full-copper DSSCs.