NANOCRYSTALLINE TITANIUM-OXIDE ELECTRODES FOR PHOTOVOLTAIC APPLICATIONS

During the past five years, we have developed in our laboratory a new type of solar cell that is based on a photoelectrochemical process. Th e light absorption is performed by a monolayer of dye (i.e., a Rutheni um complex) that is adsorbed chemically at the surface of a semiconduc tor (i.e., titanium oxide (TiO2)). When excited by a photon, the dye h as the ability to transfer an electron to the semiconductor. The elect ric field that is inside the material allows extraction of the electro n, and the positive charge is transferred from the dye to a redox medi ator that is present in solution. A respectable photovoltaic efficienc y (i.e., 10%) is obtained by the use of mesoporous, nanostructured fil ms of anatase particles, We will show how the TiO2 electrode microstru cture influences the photovoltaic response of the cell. More specifica lly, we will focus on how processing parameters such as precursor chem istry, temperature for hydrothermal growth, binder addition, and sinte ring conditions influence the film porosity, pore-size distribution, l ight scattering, and electron percolation and consequently affect the solar-cell efficiency.