Comparative study on the stability of the lead perovskite halides when irradiated with X-ray or electron beam under specific environment

Abstract

Lead halide perovskites (MAPbX₃, X = Cl, Br, I) have garnered significant attention for their potential in high-performance photovoltaics and light-emitting diodes, but their stability under analytical conditions remains a concern. In this study, we systematically investigate the denaturation processes of MAPbX₃ employing different analytical methods, including X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy, reflection electron energy loss spectroscopy, and ambient pressure XPS. The samples were exposed to X-ray and electron beam irradiation in ultra-high vacuum (UHV) and reactive gas environments (O₂ and H₂O). The denaturation process, characterized by the growth of Pb⁰ and Pb-O_x species, is most pronounced in MAPbCl₃, followed by MAPbBr₃, and least in MAPbI₃. Furthermore, MAPbX₃ samples exhibited distinct behaviors under exposure to different environments: MAPbCl₃ and MAPbBr₃ shows notable Pb-O_x formation in an O₂ atmosphere, while MAPbI₃ displays minimal oxidation. A comparative X-ray diffraction analysis revealed that low crystallinity was associated with high denaturation, even among MAPbX3 samples with identical compositions. Collectively, these findings emphasize the importance of considering both halogen composition and physical properties, such as crystallinity and morphology, when assessing the stability and reliability of lead halide perovskite materials for optoelectronic applications.