Investigations of anodization parameters and TiCl4 treatments on TiO2 nanostructures for highly optimized dye-sensitized solar cells

In this research, effects of anodization parameters on the growth behavior and top morphology of TiO2 nanotubes are investigated. Five TiO2 nanostructures with different top morphologies, including nanopores, nanotubes, nanohexagons, nanonet and nanograss, are obtained through an electrochemical anodization of Ti foil, by varying the anodization parameters, e.g., anodization time, anodization temperature and deionized water contents. Dye sensitized solar cells (DSSC) based on the photoanodes fabricated with the TiO2 nanohexagon morphology show the highest power conversion efficiency of 5.29% with N719 Dye. Moreover, to further enhance the efficiency of DSSC, modifications of the TiO2 nanohexagons with TiO2 nanoparticles derived from TiCl4 with different molar concentrations are also explored. It is observed that the TiO2 nanohexagons based photoanode treated with 0.2 M TiCl4 shows a maximum efficiency of 6.64% with N719 Dye and incident photon to-current efficiency (IPCE) of 68%, due to the increased effectiveness in electronic transport and enhanced surface area for N719 dye-adsorption.