Experimental Validation of Strong Proton Radiation Tolerance of Surface-Treated All-Inorganic CsPbI ₃ Perovskite Solar Cells for Space Applications

The rapid expansion of space-based initiatives and the increasing deployment of satellites have intensified the demand for high-performance, radiation-tolerant photovoltaics (PV). This study investigates the radiation tolerance of all-inorganic CsPbI₃ perovskites for space PV applications. Combining simulations and experimental evaluations, we compare the properties of CsPbI₃ films depending on the surface treatments using long chain cations. Octylammonium iodide (OAI) treatment forms a quasi-2D perovskite structure, whereas phenethylammonium iodide (PEAI) induces a molecular cation layer. Under harsh proton irradiation (2 × 10¹⁴ protons/cm² at 0.05 MeV), OAI-treated devices exhibited only a 19% efficiency reduction, significantly lower than the performance degradation observed in organic-inorganic hybrid perovskite PVs. Moreover, OAI treatment does not have adverse effects after irradiation, while the PEAI layer results in a severe deviation in surface electrical potential following irradiation. These findings suggest new directions for using all-inorganic PSCs in high-radiation environments, prompting further investigation into next-generation space PV technologies.