November 24, 2008 Scientists from the EU funded FULLSPECTRUM project have developed solar cells which are able to convert 39.7 percent of the energy of sunlight into electricity. The result represents the highest percentage ever reached in Europe and is more than double the efficiency of most conventional silicon-based PVs in production today.
Known as photovoltaic multi-junction solar cells, the FULLSPECTRUM design consist of different materials including gallium, phosphorus, indium and germanium and are stacked in vertical layers to make optimum use of the solar spectrum. The drawback is that multi-junction solar cells are expensive, but researchers say that the cost can be brought down by by arranging them in special panels which use lenses or concentrators to focus a solar energy onto the cells.
Increasing the viability of solar power goes hand in hand with improving the efficiency of cell design. The first solar cell built by Charles Fritts in 1883 was only around 1 percent efficient and modern cells generally achieve around 17 percent. Developments around the globe in recent times have made great strides in improving this equation with a multi-junction cell developed by Spectrolab in the U.S demonstrating 40.7 percent efficiency and new techniques such as those under development by the Idaho National Laboratory promising up to 80% efficiency. Concentrators are also seen as a critical part of achieving the overall goal of cheaper, more efficient solar energy production.
FULLSPECTRUM is an integrated project involving 19 European public and industrial research centres from seven EU Member States, as well as Russia and Switzerland.