Photochemical solar cells based on dye-sensitization of nanocrystalline TiO2

A new type of photovoltaic cell is described. It is a photoelectrochemical device that is based on the dye sensitization of thin (10-30 mu m) films of TiO2 nanoparticles in contact with a non-aqueous liquid electrolyte. The cell is very simple to fabricate and, in principle, its color can be tuned through the visible spectrum, ranging from being completely transparent to black by changing the absorption characteristics of the dye; the photovoltage of the cell is not determined by the threshold energy for light absorption (bandgap) as in conventional photovoltaic cells based on solid-state semiconductors. The highest present efficiency of the dye-sensitized photochemical solar cell is about 11%. The cell has the potential to be a low-cost photovoltaic option. Unique applications include photovoltaic power windows and photoelectrochromic windows.