Synthesis of a new class of cyclometallated ruthenium(II) complexes and their application in dye-sensitized solar cells

We synthesized a new class of cyclometallated ruthenium(II) complexes, Ru(tctpy)(C^N)(NCS) (1, 2), where C^N is a bidentate cyclometallating ligand such as 2-phenylpyridinato or 2-(4-(2-phenylethynyl)phenyl)pyridinato. Although these complexes exist as stereoisomers, the microwave synthetic technique yielded only one isomer. These compounds act as light sensitizers and have excellent light-harvesting properties, especially in the near-IR region. Therefore, they can be used in dye-sensitized solar cells (DSCs). A DSC sensitized with 2 shows a 10% incident photon-to-current conversion efficiency at 900 nm.