Novel heteroleptic Ru(II) complexes: synthesis, characterization and application in dye-sensitized solar cells

Six new heteroleptic Ru(II) complexes (MC118, MC120-123 and MC126), of general formula Ru(L1)(L2)(NCS)(2), where L1 and L2 are respectively dicarboxylated and pi-conjugated functionalized (dissymmetric) bipyridine ligands, were designed, synthesized and applied as sensitizers in dye-sensitized solar cells. These complexes were characterized both experimentally and theoretically, showing promising optical properties, with higher extinction coefficients compared to the prototypical N719 dye. When employed in working devices, in combination with a liquid I-/I-3(-) redox electrolyte, the investigated sensitizers have shown power conversion efficiencies between 6.0 and 8.0%, comparable with the reference N719 dye tested under similar fabrication and evaluation conditions.