Middle picture shows the prototype cell, millimeter scale (via Sharp)
Sure it may be small, but it’s what’s inside that counts; Sharp recently announced their record conversion efficiency rating of 43.5% for their new compound solar-cell. Known as the ‘triple-junction compound solar-cell’, the little photovoltaic cell will be used in Sharp’s lens-based concentrator system which acts as a funnel to capture the sun’s rays.
To achieve the record rating, Sharp designed the new cell using layers of indium and gallium which are alternated between three additional photo-absorption layers of photovoltaic cells. Sharp engineers then optimized the spacing of the cells surface electrodes which helps in reducing the electrical resistance encountered when converting the sun's energy into electrical power. To confirm Sharps efficiency claim, the German-based Fraunhofer Institute for Solar Energy Systems tested the tiny cell and found that it does indeed hold the world’s record for the cells energy conversion. These types of compound solar-cells are usually equipped on earth-based satellites, but Sharp hopes to employ them in Earth-based concentrator systems due of their ability to generate electricity with a relatively small surface area.