CHARGE TRANSPORT PROPERTIES IN DYE-SENSITIZED NANOSTRUCTURED TIO2 THIN FILM ELECTRODES STUDIED BY PHOTOINDUCED CURRENT TRANSIENTS

The charge transport in dye-sensitized nanostructured TiO2 was studied by laser pulse induced photocurrent transients. The experimental curves were compared to simulations using a diffusion model with an initial electron distribution of an exponential decay. The simulations were optimized with respect to the experimental curves giving an apparent diffusion coefficient of 6 × 10-6 cm2/s for the electrons with an electrolyte of 0.1 M KI in propylene carbonate, the potential being +300 mV vs Ag/AgCl in ethanol. The charge transport was highly dependent on electrolyte composition and light intensity.