Limiting efficiency of GaAs solar cells

The limiting efficiencies of GaAs solar cells when used under concentrated sunlight are calculated. An assessment of the benefits to be expected from applying techniques which restrict the angle of acceptance of the cell is made. It is concluded that by restricting the acceptance angle the emission of luminescent photons and the associated current loss are reduced. As a consequence of this effect, a limiting efficiency close to 39% results for concentration ratios of about 1000 suns AM1.5 direct. For lower concentration ratios the limiting efficiency decreases if Auger recombination is also taken into account.