Metal halide perovskites (MHPs) constitute a rich library of materials with huge potential for disruptive optoelectronic technologies. Their main strength comes from the possibility of easily tuning their bandgap to integrate them in devices with different functionalities — in principle. In reality, this cannot be achieved yet. In fact, whereas defect tolerance can be claimed for MHPs with a bandgap of about 1.6 eV, the model system that is the object of intense investigations, MHPs with lower and higher bandgaps are far from being defect-tolerant. These materials show various forms of instabilities that are mainly driven by strong defect activity. Here we critically assess the most recent advances in elucidating the physical and chemical activity of defects in both high-bandgap and low-bandgap MHPs, while correlating it to performance and stability losses, especially for solar cells, the driving application for these materials. We also provide an overview of the strategies so far implemented to eventually overcome the remaining materials-based and device-based challenges.

金属卤化物钙钛矿（MHP）构成了丰富的材料库，具有巨大的颠覆性光电技术潜力。它们的主要优势来自于可以轻松调整带隙以将它们集成到具有不同功能的设备中的可能性——原则上。实际上，这还不能实现。事实上，虽然可以对带隙约 1.6 eV 的 MHP 提出缺陷耐受性，这是深入研究的模型系统，但具有较低和较高带隙的 MHP 远非缺陷耐受性。这些材料表现出各种形式的不稳定性，主要由强缺陷活动驱动。在这里，我们批判性地评估了阐明高带隙和低带隙 MHP 缺陷的物理和化学活性的最新进展，同时将其与性能和稳定性损失相关联，特别是对于太阳能电池，这些材料的驱动应用。我们还概述了迄今为止为最终克服剩余的基于材料和基于设备的挑战而实施的策略。