Perovskite solar cells could power future long-distance space missions

A 10-month-long space trip

Various research teams are experimenting with different facets of the perovskite solar cells, but a journey through space is a different feat altogether. The solar cell will face changes in temperatures, radiation, light, and vacuum – at the same time – something that is impossibly difficult to replicate on Earth.

So, a team of researchers led by McMillon-Brown created a 1-inch by 1-inch sample in 2019, and once it passed through the stringent requirements of spaceflight, it was blasted off to the ISS in March 2020.

The sample was part of the Materials International Space Station Experiment (MISSE) platform and also became a part of a spacewalk when astronauts took it out of the ISS, opened it, and attached it to the outside of the space station to expose it to the rigors of space.

For nearly a year, the sample, along with others in the suitcase-like MISSE, orbited around the planet and went through multiple exposures to direct sunlight under the extreme conditions of space. A similar sample remained on Earth as a control for the experiment.

After the sample returned to Earth in January 2021, researchers from the University of California Merced as well as the National Renewable Energy Laboratory, performed post-flight analysis.

The researchers found that extreme temperature swings during the flight constantly expanded and shrank the sample putting it under quite a bit of stress. However, they also found that when the sample was exposed to light back on Earth, the stresses relaxed and it marked a return to its sunlight-absorbing capacities again. In contrast, the sample that remained on Earth did not exhibit similar properties.

The team also found that exposure to space also caused a rearrangement of perovskite crystals inside the solar cell and changed how they absorbed light for the better. "Not only do they survive, but in some ways, they thrived," said McMillon-Brown in a press release. "I love thinking of the applications of our research and that we’re going to be able to meet the power needs of missions that are not feasible with current solar technologies.”