Radiation-Hard and Ultralightweight Polycrystalline Cadmium Telluride Thin-Film Solar Cells for Space Applications

Achieving high-specific-power and radiation hardness of solar cells is of great importance to perform tasks and achieve duration in space. Therefore, we investigated the proton irradiation resistance of ultralightweight CdS/CdTe thin film solar cells having high specific power values. High-energy proton beams (15 MeV) with doses ranging from 1×10¹² to 1×10¹⁵ cm⁻² were used, equivalent to more than 2000 years in low Earth orbit. Although 70 % decrease in cell conversion efficiency was observed after proton irradiation with dose of 1×10¹⁵ cm⁻², it still maintained the photovoltaic performance. The specific power of the fabricated cell decreased from 358 W kg⁻¹ to 109 W kg⁻¹ after proton irradiation (dose=1×10¹⁵ cm⁻²), which is still comparable to specific powers of other types of solar cells. Our work indicated that reduction of short circuit current is a major factor of deterioration of the cell performance under the high energy proton irradiation. This work revealed that our lightweight CdS/CdTe solar cells have significant potential for the use in space applications: reduction of launch cost by achieving high specific power and assurance of durability over prolonged space missions.