It has been shown from first principles, using the integral form of the transport equations, that the efficiency of a two-junction AlGaAs-GaInAs cascade solar cell optimized at 290°K and under AM 0 spectral conditions may exceed 30%. Further studies of this cascade structure have been carried out to determine performance under AM 0-AM 5 spectral conditions and at a concentration ratio of 103 over the temperature range 290-600°K. In addition, the two-junction AlGaAs-GaInAs cascade cell has been optimized at 290°K and under AM 1.5 spectral conditions. The performance characteristics of the designs optimized under AM 0 and AM 1.5 conditions are compared over the temperature range 290-600°K. The AM 0 optimized structure was used as the initial structure to determine the optimized structure under AM 1.5 spectral conditions. The results of the computer modeling show that the optimized wide bandgap cell parameters under AM 0 and AM 1.5 are somewhat different. However, the optimized narrow bandgap cell parameters are identical for AM 0 and AM 1.5. The theoretical efficiency increases with increasing concentration ratio, approaching 40% at 103 concentration ratio. © 1979.
