Advances in Flexible and Lightweight 3J Space Solar Cells for High Power Density Applications

We are developing flexible and lightweight III-V multijunction solar cells for space applications fulfilling different power density requirements. High efficiency designs such as the 3J inverted metamorphic can achieve power densities of 3 kW/kg. Lower cost designs based on GaInP/Ga(In)As/Ge 3J lattice matched solar cells can achieve 1 kW/kg and are interesting for some space applications. In this paper we present the advances in the modelling, manufacturing and characterization of this last type of solar cell. Experimental results show that 3J solar cells thinned down to 50 mu m exhibit the same efficiency as the non-thinned solar cell (150 mu m) despite there is no passivation of the rear side, in agreement with our simulations.