Perovskite solar cells have drawn much attention recently owing to their world-record-setting photovoltaic performances, whereas their practicality is still limited by the structural instability that often arises from ion migration and defect formation. Despite the general understanding that ion instability is a primary cause for degradation, there is no observation of structural transformation at the atomistic scale. Such observation is crucial to understand how instabilities are induced by external perturbations such as illumination or electrical bias, allowing researchers to devise effective strategies to mitigate them. Here, we designed an in situ transmission electron microscopy setup to enable real-time observation of amorphization in perovskite materials under electrical biasing. To reverse the device performance degradation due to such structural changes, the samples were heated at 50 °C and were found to recrystallize, effectively regaining their performance losses. This work presents vital insights on understanding ion-migration phenomena and addressing instability challenges of perovskite optoelectronics.

中文翻译：

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电偏置下混合钙钛矿太阳能电池的实时非晶化成像

钙钛矿太阳能电池因其创世界纪录的光伏性能而最近备受关注，但其实用性仍受到离子迁移和缺陷形成经常引起的结构不稳定性的限制。尽管普遍认为离子不稳定性是降解的主要原因，但在原子尺度上没有观察到结构转变。这种观察对于了解外部扰动（如照明或电偏置）如何引起不稳定性至关重要，使研究人员能够设计有效的策略来减轻它们。在这里，我们设计了一个原位透射电子显微镜设置能够实时观察电偏压下钙钛矿材料的非晶化。为了扭转由于这种结构变化导致的器件性能下降，样品在 50 °C 下加热并发现重结晶，有效地恢复了它们的性能损失。这项工作为理解离子迁移现象和解决钙钛矿光电子学的不稳定性挑战提供了重要的见解。