Optimization of nanostructured titania photoanodes for dye-sensitized solar cells: study and experimentation of ticl4 treatment

Titanium tetrachloride (TiCl4) treatment processed by chemical bath deposition is usually adopted as preand post-treatment for nanocrystalline titanium dioxide (TiO2) film deposition in the dye-sensitized solar cell (DSC) technology. Pre-treatment influences positively the bonding strength between the fluorinated tin oxide (FTO) substrate and the porous TiO2 layer, blocking the charge recombination at the interface between the conduction glass FTO and the I3 − ions present in the I−/I3 − red-ox couple. Additionally, TiCl4 posttreatment is a widely known method capable of improving the performance of dye-sensitized solar cells, in particular, the photocurrent collected from the device. In this study, the influence and effect of TiCl4 pre- and post-treatment on the TiO2 layer is proposed and compared to the untreated film. The relative DSC devices are characterized in terms of short circuit current density, open circuit voltage, fill factor, conversion efficiency and IPCE. The dark current characteristics of cells with a treated and untreated TiO2 layer are also shown in order to evaluate the effect of TiCl4 pre-treatment as a blocking layer.