Organic–inorganic halide perovskites have emerged as a promising semiconductor family because of their remarkable performance in optoelectronic devices. On the other hand, the stability of perovskites remains a critical issue. In this work, we report a quantitative and systematic investigation of in situ cleaved MAPbBr₃ single-crystal degradation processes in X-ray, N₂, O₂, and H₂O environments. The high-quality crystals were monitored by high-resolution X-ray photoelectron spectroscopy with careful control of the exposure time and pressure. The detailed electronic structure and compositional changes of the crystal were tracked throughout the different exposures, and these studies provided insights into the various degradation mechanisms. We identified that ∼10% of the surface MAPbBr₃ degraded to metallic lead under X-rays in vacuum, while N₂ could protect the sample from the degradation for 9 h under the same condition. Other measurements showed that while the surface was not sensitive to pure O₂, it was susceptible to H₂O exposure within the top 0.37 nm and a reaction threshold of ∼10⁸ Langmuir was found. Below the threshold, H₂O acted only as an n-type dopant; above it, the surface began to decompose. These observations highlight possible future directions to improve the material stability by environmental control.

中文翻译：

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MAPbBr ₃单晶的环境表面稳定性

由于有机-无机卤化物钙钛矿在光电器件中的卓越性能，它们已成为有前途的半导体家族。另一方面，钙钛矿的稳定性仍然是关键问题。在这项工作中，我们报告了在X射线，N ₂，O ₂和H ₂中原位裂解的MAPbBr ₃单晶降解过程的定量和系统研究O环境。通过高分辨率X射线光电子能谱法对高质量的晶体进行监控，并仔细控制曝光时间和压力。在整个不同的曝光过程中，都跟踪了晶体的详细电子结构和组成变化，这些研究为各种降解机理提供了见识。我们发现，在真空条件下，X射线下约有₁₀％的表面MAPbBr ₃降解为金属铅，而N ₂可以在相同条件下保护样品9小时不受降解。其他测量结果表明，尽管该表面对纯O ₂不敏感，但在0.37 nm的顶部和〜10 ⁸的反应阈值范围内容易受到H ₂ O的暴露。朗缪尔（Langmuir）被发现。低于阈值时，H ₂ O仅充当n型掺杂剂；H ₂ O仅充当n型掺杂剂。在它上面，表面开始分解。这些观察结果突出了通过环境控制来改善材料稳定性的未来可能方向。