Low cost photovoltaic modules based on dye sensitized nanocrystalline titanium dioxide and carbon powder

A new type of photovoltaic module based on monolithically series connected dye sensitized photoelectrochemical cells is described. Each solar cell element consists of three porous layers on a transparent conducting substrate, namely a photoelectrode of dye sensitized nanocrystalline TiO2 (anatase), a spacer of electrically insulating, light reflecting particles of TiO2 (rutile), and a counterelectrode of graphite powder and carbon black. The pores of these layers are filled with a redox electrolyte containing iodide for hole transport between photo- and counterelectrode. The monolithic series connection on the transparent conducting substrate, e.g., SnO2 coated glass, is achieved by simple overlap of each carbon counterelectrode with the back contact of the adjacent photoelectrode. Such modules may be produced in a continuous non-vacuum process by simple printing techniques. In this paper we present the first results on energy conversion efficiency and long term stability obtained with this new type of solar cell.