Synthesis and characterization of a ruthenium(II) complex for photovoltaic cells

We have designed and synthesized a new ruthenium complex, [(5-amino-1, 10-phenanthroline)bis(4,4-dicarboxylic acid-2,2'-bipyridine)] ruthenium(II) by introducing two types of ligands, 5-amino-1, 10-phenanthroline and 4,4'-dicarboxylic acid-2,2'-bipyridine. We investigated the electronic, spectroscopic, electrochemical, and photovoltaic properties of the Ru(II) complex. The short-circuit current density and overall solar-to-electric energy conversion efficiency of photovoltaic cells made with this Ru(II) complex were found to be 8.9 mA/cm(2) and 2.1 %, respectively. A series of analogous Ru(II) complexes have also been synthesized and investigated to compare the effects of functional groups on various ligands. HOMO-LUMO energies and molecular orbital surfaces have been investigated using semiempirical quantum chemical methods.