A team of researchers, led by the Rochester Institute of Technology (RIT), has demonstrated a perovskite solar cell architecture that combines exceptional long‑term stability in lab testing with proven performance during a 100‑day mission in low Earth orbit (LEO). The work was led by RIT assistant professor Ahmad Kirmani, whose research at RIT is supported by a nearly $10 million U.S. Space Force grant
The study targets a key Achilles’ heel of metal halide perovskite solar cells: degradation at the interface between the perovskite absorber and the hole transport layer (HTL). Conventional polymer‑ or carbazole‑based HTLs often fail to fully cover the indium tin oxide (ITO) substrate, leaving pathways for degradation and limiting device lifetime and voltage. To address this, the team developed a “multi‑HTL” strategy in which a polymer HTL is reinforced with a phosphonic‑acid modification. This modification improves coverage and protects the buried perovskite interface, while also promoting more columnar perovskite film growth.
Devices using this reinforced HTL exhibit an open‑circuit voltage (VOC) improvement of about 40 mV, consistent with suppressed interfacial recombination across several p–i–n architectures. In accelerated durability testing, unencapsulated cells with the reinforced HTL achieved among the best reported stabilities: T90 of roughly 3,000 hours and T80 of about 5,900 hours under 1.2 sun AM 1.5G illumination at 65 °C with continuous maximum power point tracking. This represents nearly a fourfold lifetime increase compared with devices using a 2PACz‑only HTL.
Building on extensive terrestrial qualification, Kirmani’s group fabricated lightweight, thin‑film perovskite devices and subjected them to on‑ground stressors such as proton and electron irradiation, thermal cycling, and other space‑relevant conditions. A device incorporating the reinforced HTL was then integrated into a CubeSat and launched aboard a SpaceX Falcon 9 rocket into low Earth orbit at approximately the altitude of the International Space Station. Over the ∼100‑day mission, the cell operated continuously in the harsh space environment - radiation, ultraviolet exposure, extreme temperatures, vacuum - without observable degradation, maintaining performance above T80 for the duration of the flight according to the study.
The result is one of the first demonstrations of a perovskite solar cell architecture that is simultaneously optimized for terrestrial durability and validated in long‑duration space operation. With satellite launches reaching record numbers and the global space economy projected to climb into the trillions of dollars in the coming decades, scalable, low‑cost power solutions are a critical bottleneck.
