Large Area Multijunction III-V Space Solar Cells Over 31% Efficiency

This paper explores development and progress for large area III/N multijunction space solar cells with efficiencies at or above 31 %. XTJ Prime SuperCells with area over 70 cm ² , average 30.7% AMO efficiency with a maximum of 31.9%. Post radiation testing indicates an EOL efficiency of 26.7% for 1e15 1 MeVe-/cm ² fluences after ECSS annealing. Upright Metamorphic triple junction (UMM3J) devices were developed with breakthroughs in optimizing cell design and uniformity on 150 mm wafers, and demonstrated SuperCell build of average AM0 efficiency at 31.3% for 73.5 cm ² cells in area with best efficiency at 31.5%. UMM3J devices were also evaluated under typical GEO and interplanetary environments for low-irradiance and low-temperature (LILT). Finally, next generation space solar cell UMM4J devices were investigated, and high quality 1.9 eV subcells were demonstrated.