Improved efficiency of TiO2 nanotubes in dye sensitized solar cells by decoration with TiO2 nanoparticles

In the present work we investigate the effect of TiCl4 treatments on the photoconversion efficiency of TiO2 arrays used in dye sensitized solar cell. The results clearly show that by an appropriate treatment the decoration of the TiO2 nanotube arrays with TiO2 nanocrystallites of a typical size of 3 nm can be achieved. These particles can be converted to mixture of anatase and rutile phase by annealing in air. This decoration of the TiO2 nanotubes leads to a significantly higher specific dye loading and, for certain annealing treatments, to a doubling of the solar cell efficiency (in our case from 1.9% to 3.8% of AM 1.5 conditions) can be achieved.