Solution-based metal halide organic-inorganic perovskite solar cells (PSCs) have attracted considerable interest due to their remarkable properties with efficiencies now reaching >26%. Especially, flexible perovskite solar cells that are lightweight are of interest for space applications such as to power satellites. In these environments, the cells are exposed to harsh conditions such as vacuum, high temperature cycling and radiation like protons and gamma rays. Stability for space conditions for these cells is not well understood yet. As a result, PSC research has largely overlooked how these semiconductors with different substrates with different mechanical and electrical properties would behave under operational conditions in space.

PSCs, comprised of multiple organic and inorganic layers, must withstand multiple thermal cycling steps including, e.g., stress in the different materials as these have differing thermal expansion coefficients or phase transitions into different crystal symmetries of the perovskite structure changing the electrical and optical properties. This becomes especially relevant when the perovskite is cooled. Further, heating the perovskite leads to chemical decomposition, leading to a defective crystal structure. We have shown that brittle perovskites are susceptible to mechanical failure (i.e. fracture and delamination) under planar biaxial stress, chemical and structural degradation, which leads to phase segregation after each thermal cycle. In addition, current-voltage measurements were carried out to follow the performance of the solar cells through the thermal cycle.

The performance of the solar cell in space is also affected by proton and gamma radiation. This radiation is already known to cause displacement damage, defects and degradation. Through irradiation experiments, we have shown that radiation damage can be reduced by adding additional protective layers. The tested cells were still working after the radiation with added protection layers and therefore shows a way to increase the radiation hardness of the perovskite layer.

Thus, our work would be important for predicting solar cell behavior in space and is beneficial for using the knowledge gained from the temperature cycling and radiation experiment to explain the different thermal and radiation degradation behavior of perovskite solar cells.