The French Alternative Energies and Atomic Energy Commission (CEA) has confirmed that Solestial’s solar cells are able to repair radiation-related damage. Its tests have confirmed that the silicon cells effectively anneal radiation damage under sunlight at 194 F (90 C). Annealing is the process of slowly cooling to remove internal stresses of a material.
The open-circuit voltage of Solestial’s silicon solar cells dropped by only 4% and maintained 96% of their initial value after being exposed to radiation equivalent to 10 years in low Earth orbit and annealing at 194 F under one Sun illumination equivalent. The company said its 20-micron thick cells demonstrate more than 20% efficiency.
The company said the tests demonstrate the feasibility of self-curing solar cells with substantially reduced radiation-induced degradation. This is particularly important for space-based solar cells, which are buffeted by high levels of radiation and are required to operate for long lifecycles.
“Annealing of radiation damage in silicon is straightforward at high temperatures, for example, above 200 C to 250 C, but this is not useful for applications in space as these temperatures are rarely, if ever, experienced in situ,” said Romain Cariou, a space silicon solar applications expert for CEA. “The differentiation factor here is that Solestial’s cells can cure radiation damage at normal operating temperatures for solar panels in space.”