Band-Gap-Engineered Architectures for High-Efficiency Multijunction Concentrator Solar Cells

Beginning with maximum theoretical efficiencies from detailed balance calculations, we evaluate the real-world energy loss mechanisms in a variety of high-efficiency multijunction cell architectures such as inverted metamorphic 3- and 4-junction cells, as a step toward closing the gap between theory and experiment. Experimental results are given on band-gap-engineered lattice-matched and metamorphic 3-junction cells, and on 4-junction terrestrial concentrator cells. A new world record 41.6%-efficient solar cell is presented, the highest efficiency yet demonstrated for any type of solar cell.