Flexible Cu(In,Ga)Se2 Solar Cells for Outer Planetary Missions: Investigation Under Low-Intensity Low-Temperature Conditions

Commercially available flexible Cu(In,Ga)Se-2 (CIGS) solar cells are assessed at low-intensity low-temperature (LILT) conditions consistent with those expected in the outer planetary systems of Saturn, Jupiter, and Mars. In these lower temperature environments, evidence of a photo-activated barrier is observed, which is attributed to the contribution of a parasitic barrier at the CIGS/CdS interface that is mediated by metastable defect complexes. However, this barrier only results in a small reduction in performance of the solar cells under LILT conditions. Irradiation with 1.5 MeV protons at very high fluence levels are also presented, resulting in defect-related degradation. However, subsequent self-healing under annealing conditions is also observed that offers potential for sustainable performance of these systems in space conditions.