InₓGa₁₋ₓP/InₓGa₁₋ₓAs-on-Ge Solar Photovoltaic Cells

Monolithic, tandem two-junction InxGa1-xP/InxGa1-x As-on-Ge Solar Photovoltaic Cells are being developed. The cells are designed to be used with solar concentrators to generate electric power aboard spacecraft. The theoretically achievable energy-conversion efficiency of these cells under air-mass-zero (AM0) conditions and 10× concentrated solar illumination is about 33 percent. In comparison with other known dual-junction photovoltaic cells, the proposed cells would feature highest conversion efficiency and the highest specific power. The cost per unit of power of these cells would be less than the costs per unit power of GaAs and InGaP/GaAs cells. With modifications, the cells might offer similar advantages in terrestrial applications.