Spectroscopic, Electrochemical and Photophysical Properties of the Novel Complex Tetracyano-1,10-phenanthroline-5,6-dione-ruthenate(II) and its Application as a Sensitizer in Solar Cells

Abstract The new complex tetracyano-1,10-phenanthroline-5,6-dione-ruthenate(II) was synthesized as potassium and bis(triphenylphosphine)iminium salts and characterized by spectroscopic, electrochemical and photophysical techniques, with experimental results in agreement with quantum-mechanical calculations by Density Functional Theory. The structure of this anion was determined by Nuclear Magnetic Resonance. Although it emits weakly at room temperature in water with a lifetime in the nanosecond regime, the quinone moiety of the coordinated phenanthroline ligand allows its anchoring to mesoporous titanium dioxide films, thus leading to its application as a sensitizer in solar cells. Irradiated with a solar simulator, cells assembled with these dye-sensitized films, platinum as counter-electrodes and iodine/iodide redox mediators dissolved in acetonitrile or dimethylformamide, exhibit increasing efficiency of conversion of light into electrical energy with decreasing acceptor number of the solvent.