High Performance DSSC Based on Semiconducting Oxides Prepared Through Soft Chemistry Processes

DSSCs have been reported by O’Regan and Grätzel in the early nineties as a very promising alternative to conventional photovoltaic silicon devices. Main benefits of these cells are their low cost as well as their mild manufacturing process. In most of the specific literature, DSSCs are made of TiO2 films prepared by doctor-blade or screen-printing of anatase nanoparticles paste. However, due to the random organization of the nanoparticles, pore accessibility by the dye and electrolyte could be incomplete. Moreover, some anatase crystallites could suffer from a lack of connectivity, leading to electron transfer issues.

The strategy adopted by our group to improve photovoltaic efficiencies involves a templating-assisted process allowing the preparation of highly porous layers with well-ordered and accessible pores as well as improved crystallites connectivity. The main goal is to increase the film surface area and to perfectly control the mesostructure in order to maximize the adsorption of active dye and the electrolyte infiltration inside the porous network. This talk especially focuses on the templating-assisted synthesis of TiO2 and ZnO semiconducting layers used as photoelectrode in DSSCs.

Besides, due to the surface area improvement as well as the perfect control of the pore organization and the pore size, the templating strategy can be an effective solution to overcome light harvesting and solid electrolyte filling limitations encountered in solid-state DSSCs. Special effort is paid to the tuning of the TiO2 and ZnO semiconducting layers mesostructure in order to match with solid-state DSSC applications.