Ultrathin solar cells promise improved satellite performance Radiation damage to photovoltaics in orbit can be reduced by making the cells thinner

When solar cells absorb light, they transfer its energy to negatively charged electrons in the material. These charge carriers are knocked free and generate a flow of electricity across the photovoltaic. Irradiation in space causes damage and lowers efficiency by displacing atoms in the solar cell material and reducing the lifetime of the charge carriers. Making photovoltaics thinner should increase their longevity because the charge carriers have less far to go during their shortened lifetimes.

As low Earth orbit becomes more cluttered with satellites, it becomes increasingly necessary to use middle Earth orbits, such as the Molniya orbit that passes through the center of Earth’s proton radiation belt. Radiation-tolerant cell designs will be needed for these higher orbits.

Another application for radiation-tolerant cells is the study of other planets and moons. For example, Europa, a moon of Jupiter, has one of the most severe radiation environments in the solar system. Landing a solar-powered spacecraft on Europa will require radiation-tolerant devices.