40% efficient metamorphic GaInPGaInAsGe multijunction solar cells

Abstract

An efficiency of 40.7% was measured and independently confirmed for a metamorphic three-junction GaInPGaInAsGe cell under the standard spectrum for terrestrial concentrator solar cells at 240 suns (24.0 W cm2, AM1.5D, low aerosol optical depth, 25 °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 Gax In1-x As and Gax In1-x P materials, and fundamental power losses are quantified to identify paths to still higher efficiencies. © 2007 American Institute of Physics.