Space photovoltaic technologies are entering a new phase in which power generation must move beyond expensive, supply limited III–V devices toward lightweight, scalable and radiation resilient alternatives. Halide perovskite solar cells are attractive in this context because they combine high efficiency, high specific power and unusual tolerance to energetic particle irradiation. However, translating this promise into flight ready technology requires a more realistic understanding of how perovskite devices respond to the coupled stressors of orbit, including proton damage, chemical instability, interfacial degradation and rapid thermal cycling. This talk summarizes our recent progress in developing material design rules and test protocols for space compatible perovskite photovoltaics [1–4].

First, I will discuss our recent work on wide bandgap Cs/formamidinium perovskite solar cells for tandem space applications, where harsh proton irradiation revealed that damage to organic A site cations is a critical but often overlooked degradation pathway [3]. By introducing propane 1,3 diammonium iodide, we showed that A site cation stabilization can mitigate proton induced damage and support radiation recovery. Combining photovoltaic analysis with femtosecond laser ablation X ray photoelectron spectroscopy, time of flight elastic recoil detection analysis and time resolved Kelvin probe force microscopy allowed us to connect device level recovery with nanoscale chemical and electrostatic changes [3].

Second, I will present our study of all inorganic CsPbI₃ perovskite solar cells, where surface chemistry was used to control the radiation response under low energy proton irradiation [2]. Octylammonium iodide treatment formed a quasi 2D surface structure and enabled devices to retain most of their initial performance after 0.05 MeV proton irradiation at 2 × 10¹⁴ protons cm⁻². In contrast, phenethylammonium iodide induced a molecular cation layer that led to severe surface potential deviation after irradiation. These results show that radiation tolerance is governed not only by the inorganic absorber lattice, but also by the surface treatment chemistry and its interaction with proton induced charge redistribution [2].

Third, I will discuss cerium oxide incorporation as a multifunctional strategy for improving both radiation tolerance and operational stability [4]. CeOx nanoparticles introduced through an octylammonium iodide assisted treatment improved crystallinity, reduced defect density and enhanced interfacial energy alignment. The treated devices reached high efficiency and showed improved retention after proton irradiation, while also demonstrating enhanced photothermal stability under coupled space relevant stress conditions [4].

Finally, I will show why radiation testing alone is insufficient for space qualification. By analysing low Earth orbit temperature profiles, we established an accelerated thermal shock protocol from −80 °C to +80 °C at 16 °C min⁻¹ for 100 cycles [1]. Using FAPbI₃ as a model system, we found that controlled MAPbBr₃ incorporation suppressed microstrain and δ phase formation after thermal shock, and validated the laboratory findings through near space balloon exposure at 35 km [1]. Together, these studies provide a framework for moving perovskite photovoltaics from promising radiation tolerant materials toward robust, testable and ultimately deployable space power technologies.

References

[1] Lee, M. et al. Energy & Environmental Science 2026, 19, 2557–2568. DOI: 10.1039/D5EE03704B.

[2] Shim, H. et al.  Nano Letters 2026, 26, 1366–1374. DOI: 10.1021/acs.nanolett.5c05407.

[3] Shim, H. et al.  Joule 2025, 9, 102043. DOI: 10.1016/j.joule.2025.102043.

[4] Lee, M. et al . ACS Energy Letters 2026, 11, 389–400. DOI: 10.1021/acsenergylett.5c02116.