Development of lightweight space solar cells with 30% efficiency at end-of-life

AZUR´s latest lattice-matched triple junction space solar cell product has been designed for a high EOL efficiency by focusing the development on radiation hardness right from the beginning. These solar cells named as 3G30-Advanced show an efficiency of 29.5% at BOL and of 28.1% for EOL at 5E14 (1MeV) e-/cm² (AM0, 1367 W/m², 28°C). Meanwhile more than 125,000 cells of this cell type have been delivered to customers worldwide. Cell thicknesses of 150 μm, 80μm or even as thin as 20μm are available. Besides the standard size of 8×4 cm² (with cropped corners) larger sizes such as 8×8cm² and 12×6 cm² are also available and provide equal performance. AZUR´s next generation product will comprise a metamorphic 4-junction device targeting at 30% efficiency at EOL to be qualified in 2015/16. Furthermore, for arriving at more than 30% EOL efficiency with 4 - 6 junction solar cells in a subsequent step, appropriate lattice-matched 1eV dilute nitride materials, inversely grown solar cells and semiconductor bonded cells are studied in cooperation with external partners.