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[Display omitted] • The modification of perovskites by partial replacement of Pb2+ with Dy2+ was explored. • Incorporation of Dy2+ strongly enhanced resistance of perovskite films to gamma rays. • The presence of Dy2+ suppressed metallic lead Pb0 formation upon radiolysis. • Dy modification improved the tolerance of perovskite films to 8.5 MeV electron beams. • Excellent radiation hardness of Dy-loaded absorbers points to aerospace applications. Continuously growing evidence of the excellent radiation hardness of perovskite solar cells stimulates their intense exploration in the context of potential aerospace applications. However, there is still a very limited understanding of the fundamental aspects such as the mechanisms of the interaction of complex lead halides with different types of ionizing radiation and associated aging pathways, even though this knowledge is essentially important for the development of new materials with improved properties. Herein, we made one of the first steps to fill this gap through a systematic study of the aging behavior of two perovskite absorber materials under exposure to three different stressors: 60Co gamma-rays, 8.5 MeV electron fluences, and light. The application of a set of complementary spectroscopy and microscopy techniques allowed us to identify and compare perovskite degradation pathways caused by each type of the ionizing radiation. In particular, radiation-induced phase segregation with the formation of δ-phases of CsPbI 3 and FAPbI 3 appears to be a common route in the case of double cation perovskites. Most importantly, we have revealed that the incorporation of dysprosium cations as a replacement of 1 % of Pb2+ ions in the Cs 0.12 FA 0.88 Pb 0.99 Dy 0.01 I 3 material formulation results in a remarkably improved radiation hardness: this modification blocks the formation of metallic lead and strongly suppresses segregation of Cs-rich and FA-rich phases in perovskite films under exposure to gamma rays or high-energy electrons. Thus, these results open up a promising research direction for designing radiation-resistant perovskite absorbers through rational compositional engineering. [ABSTRACT FROM AUTHOR]

The toxicity of complex lead halides significantly limits the commercialization and practical application of perovskite solar cells. In recent days, lead-free complex lead halides with a perovskite structure have become increasingly popular, among which germanium systems are the least studied. Here we present for the first time a systematic study of the thermal and photochemical stability of perovskite thin films of CsGeI 3 and CsGeBr 3. The measurements of optical absorbance and X-ray photoelectron spectra (XPS) of core levels and valence bands of Ge-based halide perovskites after light soaking and heat stress were thoroughly performed. It has been found the effect of thermal and photochemical degradation of Ge perovskites which is accompanied by reduction of I:Ge and Br:Ge ratios and appearance of tetravalent metal species fixed in XPS Ge 2p and Ge 3d spectra. The XPS O 1s measurements of irradiated and annealed Ge-based perovskites and their comparison with spectra of GeO 2 have shown that formation of Ge4+-species is not due to metal oxidation but owing to defect-mediated hole-doping. While the Ge2+→Ge4+ process lowers the thermal and photochemical stability of Ge-based perovskites and limits their use in photovoltaics, the temperature induced hole doping is favorable for thermoelectric applications. • A systematic study of the thermal and photochemical stability of perovskite films of CsGeI 3 and CsGeBr 3 are presented. • The degradation of Ge perovskites is accompanied by reduction of I:Ge and Br:Ge ratios and appearance of tetravalent metal species. • The formation of Ge4+-species is not due to metal oxidation but owing to defect-mediated hole-doping. [ABSTRACT FROM AUTHOR]