Effects of 10-Month Low Earth Orbit Exposure on Hybrid Perovskite Thin Film

The high defect tolerance and potential for extremely high specific power in metal-halide perovskite (MHP) solar cells makes them promising materials for space-based photovoltaics. Additionally, moisture, by far the most significant variable in perovskite degradation, is negligible outside the earth’s atmosphere. In this work, we examine the effects of low earth orbit (LEO) on a MHP sample via optical characterization. An encapsulated methylammonium lead iodide film was flown to the International Space Station as part of the 13^th Materials International Space Station Experiment and exposed to the LEO environment for 10 months. The sample underwent 45 minutes of AM0 illumination and 45 minutes of darkness a total of 4800 times, resulting in thermal variation between 100° C and -100° C. The flight sample emitted a strong photoluminescence signal and showed little degradation. Our analysis suggests that severe temperature cycling had the greatest impact on the film. After 15 hours of AM1.5 illumination, the flight sample’s bandgap red-shifted to match that of its control sample. Likewise, confocal microscopy revealed a reduction in lead iodide in the flight film after light soaking. These behaviors indicate photo-annealing within the film and demonstrate that MHPs can withstand space stressors.