Quasi-2D perovskites have been pivotal in recent efforts to stabilize perovskite solar cells. Despite the stability boost provided when these materials are introduced in perovskite solar cells, little is known about the intrinsic light and environmental stability of quasi-2D perovskites. In this study, we characterize the photostability of exfoliated quasi-2D perovskite single crystals in air using photoluminescence, infrared, X-ray fluorescence, and energy-dispersive X-ray spectroscopy. Photoexcitation leads to severe material loss with oxygen as a prerequisite for material breakdown. The effect can be traced to the formation of reactive oxygen species, as demonstrated by increases in the photostability under oxygen-free conditions. We show the effect of combined passivation steps, showcasing the stability enhancement offered by 2D-capping layers in combination with an oxygen-free atmosphere. Our results reveal that the stability of illuminated quasi-2D perovskites depends critically on oxygen exposure, highlighting the importance of oxygen-blocking passivation strategies for stable 2D perovskite-based devices.

中文翻译：

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大气暴露会触发 2D 卤化铅钙钛矿中的光诱导降解


准 2D 钙钛矿在最近稳定钙钛矿太阳能电池的努力中发挥了关键作用。尽管将这些材料引入钙钛矿太阳能电池时提供了稳定性提升，但人们对准 2D 钙钛矿的固有光和环境稳定性知之甚少。在这项研究中，我们使用光致发光、红外、X 射线荧光和能量色散 X 射线光谱表征了剥离的准 2D 钙钛矿单晶在空气中的光稳定性。光激发会导致严重的材料损失，氧气是材料分解的先决条件。这种效应可以追溯到活性氧的形成，无氧条件下光稳定性的增加证明了这一点。我们展示了组合钝化步骤的效果，展示了 2D 加帽层与无氧气氛相结合提供的稳定性增强。我们的结果表明，照明准 2D 钙钛矿的稳定性在很大程度上取决于氧暴露，突出了氧阻断钝化策略对于稳定的 2D 钙钛矿基器件的重要性。