Abstract
All-inorganic perovskite materials, such as CsPbX3 (X = I, Br), have attracted significant attention due to their chemical robustness and optoelectronic properties, which enable high power conversion efficiencies (PCE) in solar cells. Among them, CsPbI2Br, obtained by partial substitution of iodide with bromide ions, is of particular interest: this material offers an optimal balance between bandgap (1.92 eV) and stability, making it promising for optoelectronic applications, including tandem solar cells. At the same time, CsPbI2Br is prone to light-induced halide segregation, which leads to the formation of bromide-rich and iodide-rich domains and, consequently, to the degradation of photophysical properties . Moreover, exposure to ionizing radiation also triggers halide phase segregation, further limiting the material's stability under intense irradiation conditions. Given the growing interest in deploying perovskite solar cells in spacecraft and other radiation-intensive environments, a comprehensive assessment of their radiation tolerance becomes a prerequisite for practical implementation. It is precisely for this reason that understanding the mechanisms of radiation-induced degradation and developing approaches for its suppression represent a key challenge toward the application of PSCs in areas where conventional silicon photovoltaics face serious weight and cost constraints. To overcome halide phase segregation, various approaches have been proposed, ranging from organic passivation or B-site compositional engineering, where Pb2+ is partially replaced by other metal cations2. In the present study, we have demonstrated that light-induced phase segregation can be effectively suppressed through appropriate compositional engineering. Furthermore, the developed materials and devices based thereon exhibit high radiation and thermal stability, which is a decisive factor for their operation in extreme environments—in outer space or in settings with high levels of ionizing radiation. Thus, the obtained results provide valuable insights for the targeted optimization of the performance and durability of all-inorganic perovskites for advanced optoelectronic technologies. This work was supported by the Russian Science Foundation (project No. 22-13-00463-P).