A number of studies investigating the electronic structure of well-defined lead halide perovskite surfaces have emerged in the last five years. Surfaces and their interfaces can not only have considerable effects on the performance of devices such as solar cells but also open a window into the intrinsic electronic properties of lead halide perovskites. This is particularly true for angle-resolved photoelectron spectroscopy, which is possibly the technique giving the most direct access to the electronic (band) structure of a material. The pump–probe version of the technique, two-photon photoelectron spectroscopy, gives information about the femtosecond and picosecond electron dynamics following optical excitation. This review summarizes the recent progress made using these surface-sensitive techniques. In addition, differences between the optical and electronic properties between the near-surface (hundreds of nm) and the deep bulk material of single crystals are discussed. We point out critical issues concerning the comparability between individual results arising from the different depths and timescales probed, or from differing environmental conditions such as the temperature or the surrounding atmosphere.

中文翻译：

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卤化铅钙钛矿的表面电子结构和动力学

在过去的五年中，出现了许多研究明确定义的卤化铅钙钛矿表面电子结构的研究。表面及其界面不仅可以对太阳能电池等器件的性能产生相当大的影响，还可以为了解卤化铅钙钛矿的内在电子特性打开一扇窗户。对于角分辨光电子能谱来说尤其如此，这可能是最直接访问材料电子（能带）结构的技术。该技术的泵-探针版本，双光子光电子能谱，提供有关光激发后飞秒和皮秒电子动力学的信息。本综述总结了使用这些表面敏感技术取得的最新进展。此外，讨论了近表面（数百纳米）和单晶深块材料之间的光学和电子特性之间的差异。我们指出了有关由不同深度和时间尺度探测或不同环境条件（如温度或周围大气）引起的个体结果之间可比性的关键问题。