Are metal-halide perovskite solar cells really radiation tolerant?

Recent evidence of radiation tolerance and self-healing in metal-halide perovskites has spurred interest in their potential as a scalable and low-cost space power technology for the emerging commercial space economy. In this perspective, we challenge the prevailing narrative around this radiation tolerance, suggesting that perovskites may not be as tolerant as currently perceived and that further work is needed to fully understand radiation-matter interactions in these systems. We suggest that a unique combination of lattice softness, strong electron-phonon coupling, and low intrinsic thermal conductivity places halide perovskites in a category of unconventional semiconductors, enabling them to self-heal from radiation-induced displacement damage, unexpected for structurally vulnerable materials. Nevertheless, we postulate that the tendency for halide perovskites to self-heal might also be their Achilles' heel, making them vulnerable to ionizing radiation that involves sharp localized phonon-mediated temperature spikes and decomposition at higher radiation fluence. Calling attention to this unusual characteristic, we attempt to spur the development of theoretical and experimental insights with the goal of realizing tailored device architectures that can withstand coupled extremes where radiation, thermal cycling, vacuum, and air mass 0 (AM0) illumination join forces and inflict catastrophic nonlinear damage.