Radiation Characteristics and Mission Considerations in Lithium-Containing Solar Cells

Empirical relations between post-irradiation photo-voltaic parameters and lithium-donor density gradient have been derived for crucible-grown lithium-containing solar cells irradiated by i MeV electrons to fluences from 3 × 1013 to 3 × 1015e/cm2. Open-circuit voltage increases logarithmically with lithium gradient both immediately after irradiation and after completion of recovery. A particularly strong gradient dependence after recovery from 3 × 1015e/cm2 indicates the need for high lithium gradients (> 5 × 1018cm-4) to maintain satisfactory cell performance after heavy electron irradiation. These, together with previously reported results (l) provide the basis for a mission compatibility analysis for crucible-grown lithium cells in an electron-dominated radiation environment.