Third Generation Solar Cell

The electrochemical dye solar cell was invented in 1988 by Professor graetzel of Lausanne Polytechnique, in Switzerland. The “Graetzel” dye cell uses dye molecules adsorbed onto the nanocrystalline oxide semiconductors such as TiO2 to collect sunlight. Dye cells employ relatively inexpensive materials including glass, Titania powder and carbon powder. Graetzel’s cell is composed of a porous layer of titanium dioxide nanoparticles, covered with a molecular dye that absorbs sunlight, like the chlorophyll does in green leaves. The titanium dioxide is immersed in an electrolyte solution, above which is a platinum-based catalyst. As in a conventional alkaline battery, an anode (the titanium dioxide) and a cathode (the platinum) are placed on either side of a liquid conductor (the electrolyte). Sunlight passes through the cathode and the conductor, and then withdraws electrons from the anode, at the bottom of the cell. These electrons travel through a wire from the anode to the cathode, creating an electrical current.