The most efficient silicon solar cells capture about 25 percent of the sun’s energy. Multijunction solar cells combine several materials to capture multiple bands of photonic energy. Today’s most efficient combination — germanium, gallium arsenide and gallium indium phosphide — boosts efficiency to 36 percent, but is relatively difficult to make and therefore expensive. Researchers from Lawrence Berkeley National Laboratory, the University of California, and the Massachusetts Institute of Technology have engineered a single material that contains three bandgaps. The material is capable of capturing more than 50 percent of the sun’s energy, said Wladek Walukiewicz, a senior staff scientist at the Lawrence Berkeley National Laboratory.
May 7th, 2004