25-Percent efficient low-resistivity silicon concentrator solar cells

Recent improvement in the performance of silicon solar cells has produced outstanding energy conversion efficiencies of 27.5 percent by the use of high-resistivity rear-contacted cells. Parallel improvements in the more conventional bifacially contacted low-resistivity cells are described which have increased the efficiencies of such devices to 25 percent in the 50-100-suns concentration range. Efficiencies of 22 percent under one-sun concentration are also reported, comparable to those obtained with the high-resistivity approach, although not directly comparable to efficiencies for nonconcentrating cells for reasons outlined.