InGaP/Ge and GaAs/Ge Double-Junction Solar Cells for Thermal-CPV Hybrid Energy Systems

We demonstrate the feasibility approach to deploy two types of dual junction GaInP/Ge and GaAs/Ge solar cells in a hybrid photovoltaic-solar thermal concentrator system, where they can operate at 250 degrees C and at medium light concentration. These devices were designed to transfer absorbed heat to tube with a fluid, using high thermal conductivity of Ge substrate. Both heterostructures showed no significant degradation after a high temperature thermal storage of over 7 months long. Regarding their performance, the GaAs/Ge dual junction showed similar to 1% higher absolute efficiency than the InGaP/Ge, at 250 degrees C and 170 suns.