Radiation Effects on High Efficiency Silicon Solar Cells

The performance of 10 cell types from 3 manufacturers shows non-irradiated, glass-covered cell efficiencies ranging from 10.3 to 13. 6% after prolonged photon illumination for cells having thicknesses from 215 to 370 μm. Efficiencies after irradiation by 1-MeV electrons to a fluence of 1E15 e/cm2 ranged from 8.0 to 9.2 percent. The degradation in power output as a result of 1E15 e/cm2 irradiation ranged from 31 to 32% for cells with a 2 ohm-cm base resistivity and from 28 to 30% 0 for 10 ohm-cm cells. Cells having a P+ back surface field showed the highest degradation in each resistivity group. Only a cell group using float-zone material showed significant photon degradation after electron irradiation. All other cell types showed annealing of electron irradiation damage of up to 5% after 3E15 e/cm2 irradiation. The solar absorptance for the high efficiency cells ranges from 0.78 to 0.93.