Dye Sensitized Solar Cells Using Freestanding TiO2 Nanotube Arrays

A TiO2 photoanode was prepared by depositing TiO$_{2}$ nanoparticle on the FTO glass followed by placing TiO$_{2}$ nanotube arrays on the top of TiO$_{2}$ nanoparticle film. The resulting TiO$_{2}$ nanotube/nanoparticle photoanode was sensitized with N719 dye after TiCl$_{4}$ treatment and exposure to O$_{2}$ plasma. The resulting dye sensitized solar cell (DSSC) showed that the highest DSSC power conversion efficiency of 8.02{\%} and 7.00{\%} were yielded when a 20 $\mu $m thick TiO$_{2}$ nanoparticle and a 13/7 $\mu $m TiO$_{2}$ nanoparticle/nanotube were used as photoanode, respectively. The I$\sim $V curve analysis suggested that the nanotubes had better electron transport pathway but lower electron generation. Future work will be focused on increasing the dye loading of nanotubes to improve the power conversion efficiency.