40% efficient metamorphic GaInP/GaInAs/Ge multijunction solar cells

An efficiency of 40.7% was measured and independently confirmed for a metamorphic three-junction GaInP/GaInAs/Ge cell under the standard spectrum for terrestrial concentrator solar cells at 240 suns (24.0 W/cm(2), AM1.5D, low aerosol optical depth, 25 degrees C). This is the initial demonstration of a solar cell with over 40% efficiency, and is the highest solar conversion efficiency yet achieved for any type of photovoltaic device. Lattice-matched concentrator cells have now reached 40.1% efficiency. Electron-hole recombination mechanisms are analyzed in metamorphic GaxIn1-xAs and GaxIn1-xP materials, and fundamental power losses are quantified to identify paths to still higher efficiencies. (c) 2007 American Institute of Physics.