Space Solar Cells - 3G30 and Next Generation Radiation Hard Products

Abstract

The 3G30-Advanced, AZUR SPACE's latest qualified solar cell product, provides highest end-of-life efficiencies in space. The cell reaches 27.8% at a fluence of 5 E14 cm-2 and 26.5% at a fluence of 1 E15 cm-2 1 MeV electrons. The cell mass can be reduced to a minimum by substrate thinning, the cell cost can be reduced by implementation of large area configurations and even higher radiation hardness can be achieved by using AZUR's proprietary 3G30-1E16+ design. Various configurations are currently in production. The increasing demand for cells suited for LEO applications, made AZUR to develop a novel upright metamorphic triple junction solar cell with a BOL efficiency of 31% designed for a fluence of 1 E14 cm-2 1 MeV electrons. This cell design is already in production. AZUR's next generation product 4G32 comprises an upright metamorphic 4-junction device with 28.5% EOL (1 E15 cm-2 1 MeV electrons) efficiency. Hence, the 4G32 even surpasses the EOL efficiency of the lattice-matched 3-junction cell 3G30-Advanced. It utilizes the excess current of the Ge subcell by a metamorphic cell concept and a fourth junction added to the stack. This cell will be qualified by mid-2017. This paper summarizes the results and achievements for various 3G and 4G solar cell products from AZUR SPACE, including radiation hardness and cell formats.