Photosensitization of ITO and nanocrystalline TiO2 electrode with a hemicyanine derivative

The monochromophore (E)-N-Hexadecyl-4-(2-(4-diethylamino)phenyl)ethenyl) py ridinium stearate was synthesized. The LB film of the dye-modified ITO give s rise to cathodic photocurrent, while the dye-sensitized nanocrystalline T iO2 film generates anodic photocurrent. Having investigated some factors su ch as electron donor and acceptor, and bias voltage that may affect the mag nitude of photocurrent and the direction of current flow, we proposed a mec hanismic model for photocurrent generation. The quantum yield is about 0.2% for monolayer LB film-modified ITO electrode and 1.0% for the dye-sensitiz ed nanocrystalline TiO2 film under irradiation of 469-nm light in 0.1 M KCl aqueous solution without applied potential. Under 100 mW/cm(2) illuminatio n of simulated solar light, the dye-sensitized nanocrystalline TiO2 film ge nerated greater than 1 mA/cm(2) of current density, which is comparatively high among the organic dyes. (C) 2000 Elsevier Science S.A. All rights rese rved.