Point defects in metal halide perovskites play a critical role in determining their properties and optoelectronic performance; however, many open questions remain unanswered. In this work, we apply impedance spectroscopy and deep-level transient spectroscopy to characterize the ionic defect landscape in methylammonium lead triiodide (MAPbI₃) perovskites in which defects were purposely introduced by fractionally changing the precursor stoichiometry. Our results highlight the profound influence of defects on the electronic landscape, exemplified by their impact on the device built-in potential, and consequently, the open-circuit voltage. Even low ion densities can have an impact on the electronic landscape when both cations and anions are considered as mobile. Moreover, we find that all measured ionic defects fulfil the Meyer–Neldel rule with a characteristic energy connected to the underlying ion hopping process. These findings support a general categorization of defects in halide perovskite compounds.

金属卤化物钙钛矿中的点缺陷在决定其性能和光电性能方面起着至关重要的作用。但是，许多悬而未决的问题仍未得到解答。在这项工作中，我们应用阻抗光谱和深层瞬态光谱来表征三碘化铅（MAPbI _3）中的离子缺陷态钙钛矿，其中有意通过部分改变前体化学计量来引入缺陷。我们的结果强调了缺陷对电子环境的深远影响，例如其对设备内置电势的影响，以及对开路电压的影响。当阳离子和阴离子都被认为是可移动的时，即使低离子密度也会对电子环境产生影响。此外，我们发现所有测得的离子缺陷均符合Meyer–Neldel规则，并且具有与潜在的离子跳跃过程相关的特征能量。这些发现支持卤化物钙钛矿化合物中缺陷的一般分类。