Efficient sensitization of nanocrystalline TiO2 films with high molar extinction coefficient ruthenium complex

A novel heteroleptic polypyridine ruthenium complex, cis-Ru(L1)(L2)(NCS)2, L1 = 4,4′-dicarboxylic acid-2,2′-bipyridine (dcbpy), L2 = 4,4′-bis[p-diethylamino]-α-styryl]-2,2′-bipyridine, was synthesized. The dye displays extremely high molar extinction coefficient, which is comparable with organic dye. Preliminary test shows the dye-sensitized TiO2 solar cell gives high conversion efficiency up to 8.65% under 1 Sun, while 8.35% is given for N3 based DSCs under the same condition. The dye will be further employed in solid state DSCs with hole transport material.