Cyclometalated ruthenium chromophores for the dye-sensitized solar cell

The recent finding that cyclometalated Ru(II) chromophores can generate high power conversion efficiencies (η) in the dye-sensitized solar cell (DSSC) has ushered in a new era of dye development. This class of dyestuff not only leaves open the opportunity to circumvent the labile monodentate NCS− groups that constitute conventional high performance dyes (e.g., [Ru(dcbpy)2(NCS)2]; dcbpy = 4,4′-dicarboxy-2,2′-bipyridine (N3) and derivatives thereof), but also offers unprecedented control of the frontier molecular orbitals for DSSC dyes. Indeed, complexes bearing aromatic cyclometalating ligands enable the manipulation of both the ground- and excited state reduction potentials through the judicious installation of substituents. This review outlines how the new and rapidly expanding class of Ru-based sensitizers bearing bidentate and tridentate cyclometalating ligands provide a conduit for potentially enhancing the stability and performance of the DSSC, gaining new insight into interfacial electron-transfer and dye regeneration processes, and utilizing new redox mediators in the DSSC.

.Figure optionsDownload high-quality image (122 K)Download as PowerPoint slideHighlights
► Review of cyclometalated ruthenium sensitizers in the dye-sensitized solar cell.
► Cyclometalated ligands offer unprecedented control of frontier energy levels for DSSCs.
► New paradigm of DSSC dyestuff.