Abstract
We have conducted the synthesis of 2 wide bandgap semiconducting nanomaterials: single crystalline ZnO nanowires and pure-anatase TiO2 nanoparticles by using catalyst-free thermal evaporation and hydrothermal methods, respectively. The surface-roughness-assisted vapor-solid growth mechanism of ZnO nanowires has been discussed in which the roughness-dependence of nanowire diameter is discovered and the selective-area growth of ZnO nanowire array can be achieved successfully based on this above mechanism without using either catalysts or seedlayers. Transmission electron microscope and x-ray diffraction have been used to characterize both of nanomaterials. ZnO nanowires and TiO2 nanoparticles have been applied for photoanode materials in dye-sensitized solar cell. Dye-sensitized solar cells with ZnO nanowires and TiO2 nanoparticles have been fabricated with conversion efficiencies of 1.33% and 8.86% and fill factors of 0.52 and 0.71, respectively. The efficiency 1.33% of the former is improved due to the use of high crystalline ZnO nanowires. Electrochemical impedance spectroscopy has been also used to analyze properties of charge transport and recombination of the latter. The resistivity of TiO2 photoanode under illumination is obtained.