Photophysical properties of new cyclometalated ruthenium complexes and their use in dye sensitized solar cellsElectronic supplementary information (ESI) available: H-NMR spectra of L65-L71 and T65-T71 are shown. See DOI: 10.1039/c2dt30482a

A new class of cyclometalated ruthenium complexes, Ru(C^N^N)(N^N^N)·Cl where N^N^N = 4,4,4-tricarboxy-2,2:6,2-terpyridine and C^N^N = substituted 6-phenyl-2,2-bipyridine, for Dye Sensitized Solar Cells (DSSCs) is proposed. We have investigated the effect of different substituents (R = COOH, thiophen-2-yl, F and OCH 3 ) on the ancillary C^N^N ligand on the photophysical properties and performance of the six different cyclometalated ruthenium complexes in DSSCs. Using an ionic liquid based electrolyte, efficiencies up to = 3.06% have been attained under 1 sun irradiation. Moreover, the T66 based DSSC exhibited a good stability under 1000 W m 2 light soaking at 60 °C for 24 days, retaining 92.8% of its initial efficiency. Cyclometalated ruthenium complexes, Ru(C^N^N)(N^N^N)·Cl with different substituted ancillary ligands have been investigated in Dye Sensitized Solar Cells.