The Duong

Perovskite solar cell (PSC) technology is a promising candidate for space applications because of its high power‐to‐weight ratio, low‐cost fabrication process, and good tolerance to high‐energy particle radiation. In this work, perovskite films and resultant high‐efficiency PSCs are assessed under 10 MeV proton radiation at fluences in the range 1e12–1e14 p cm −2 , which are equivalent to 1 to 100 years in geostationary orbit (GEO) without any shielding or cover. For the first time, void formation and material ablation are detected on perovskite films, indicating structural damage of the materials under the proton radiation. Furthermore, ions inside the devices especially Au and Pb ions are displaced to underlying layers under the proton bombardment. These lead to the degradation of PSCs to ≈89% of the initial performance (from 24.1% to 21.4%) at the highest dose. The experimental results are supported by previous simulation works with a good fit in all optoelectronic parameters. This study provides insights into the degradation mechanism of PSCs under proton radiation and paves the way for the utilization of PSCs in space applications.

The key role of Cs cation and X halide anions (X = I, Br, Cl) on the microstructure, crystal structure, structural defects, optoelectronic properties, and photovoltaic parameters of FAPbI 3 ‐based perovskite solar cells is investigated. The CsCl–FAPbI 3 perovskite film shows the highest photoluminescence (PL) intensity, longest PL lifetime, and highest power conversion efficiency compared with the CsI–FAPbI 3 and CsBr–FAPbI 3 perovskite films. The morphology and crystallography of c nanotwins and stacking faults of perovskite films are studied using transmission electron microscopy and selected‐area electron diffraction. The microstructure, crystallography, and atomic structure model of intersecting twin boundaries are presented. Finally, the degradation pathways and the mechanism behind the formation of FAPbI 3 ‐based perovskites under ambient conditions are systematically studied. The grain boundaries of the perovskite films are nonuniformly damaged, resulting in many black nanoparticles after 4 weeks. Electron diffraction analyses of the black nanoparticles confirm the hexagonal PbI 2 phase formation in all CsX–FAPbI 3 perovskite samples after 4 weeks of aging.