Recent advances in the fabrication of  inexpensive nanocrystalline materials such as TiO₂ in conjunction with the synthesis of stable photosensitizers (e.g., Ru(II)-polypyridyl complexes) that covalently bond to these materials has allowed construction of robust electrode systems and liquid solar cells that show efficient conversion of visible light to electrical energy.  (For example, see O’Regan, B; Grätzel, M.  Nature 1991, 353, 737, for an often-cited reference.)

  Current efforts in our research group, funded by the Petroleum Research Fund of the American Chemical Society, focus on exploiting this technology by attaching photoactive metal complexes of biologically active ligands to TiO₂-coated transparent electrodes.  Our goal is to promote photoassisted H-atom transfer reactions in order to catalyze chemical transformations using visible light.  In other words, we wish to construct solar cells that are capable of using sunlight to provide the energy for chemical synthesis (i.e., artificial photosynthesis).