The conversion efficiency limit of p+-i-n+ silicon solar cells in concentrated sunlight is explored with numerical simulations of an idealized p+-i-n+ cell having field-induced junctions. Conversion efficiencies greater than 30 percent are calculated for this cell operating in sunlight concentrated 1000 times. The relative importance of bulk and surface recombination in limiting the cell conversion efficiency is illustrated for operation in 1 to 1000 suns. For surface recombination velocities below 100 cm/s, it is shown that bulk recombination losses limit the cell performance rather than recombination losses occurring in the p+ or n+ regions. The results show that Auger recombination in the bulk region will limit ultimately the cell conversion efficiency. © 1980 IEEE.