Perspectives for application of amorphous silicon thin-film solar cells in conditions of higher-level space radiation

Potential application of thin-film amorphous silicon solar cells for power generation on board spacecraft designed to operate in orbits with high-intensity fluence of electrons and protons, in the radiation belts of the Earth are discussed in this paper. The three-junction solar cells based on the amorphous silicon and germanium alloy with the substrate of 25 microns steel foil were the baseline specimen for this research work. Such solar cells had the initial efficiency of 10%, measured at AM0. The laboratory tests involved irradiation of the amorphous silicon based solar cells with 3 MeV electrons and 20 MeV protons and demonstrated their high resistance to radiation. Taking into account this fact, also very favorable cost-effectiveness and power-to-weight characteristics, as well as affirmative results from the orbital flight test of an a-Si solar array on board of MIR space station, this paper gives an assessment of functional capabilities of the a-Si cells for application in the Earth orbits with a high radiation level.