Synthesis and Characterization of a New Novel Dye Sensitizer for Nanocrystalline TiO2-Based Solar Cells

Sina Yeganeh
California Institute of Technology

A new sensitizing ruthenium(II) dye has been synthesized bearing a unique ligand with propynoic acid functionality. The metal complex [RuII(4'-carboxyethynyl-[2,2']bipyridinyl-4-yl)-propynoic acid)2 (NCS)2] was prepared and was characterized by UV-vis, emission, and time-resolved laser spectroscopy. Experiments were carried out both with the dye in solution as well as in its bound state on a TiO2 electrode. Formal oxidation potentials for the dye were found through electrochemical methods. Solar cells utilizing the synthesized dye were constructed, and their solar-to-electric conversion efficiencies were determined under standard AM 1.0 sunlight. By separating the metal center from the TiO2 surface by a small distance, the influence of surface effects on the various recombination pathways in the cell were examined.