AlGaInP/GaAs 27% Efficient Top Solar Cells

AstroPower will develop a two-junction monolithic tandem solar cell composed of (AlxGa1-x)0.51 In(0.49)P, which is lattice matched to GaAs, as the top cell in a three-junction, two-terminal tandem solar cell. This new tunable bandgap Al-Ga-In-P material is capable of current matching in a two-junction monolithic tandem solar cell two-terminal design of the Al-Ga-In-P over GaAs yielding a best case predicted efficiency of 27.2%. The direct bandgap of the material system can be tuned to as high as 2.3 eV, where a bandgap of 2.03 eV is necessary for current matching in a two-terminal stack. The tandem solar cell can in turn be applied as a current-matched top solar cell in a triple-junction, two terminal configuration with silicon or other suitable bottom solar cells. The success of this project will lead to deployment of high performance solar cells in the space environment, and will impact the longevity and power generation of space power supplies.