Materials with highly crystalline lattice structures and low defect concentrations have classically been considered essential for high-performance optoelectronic devices. However, the emergence of high-efficiency devices based on halide perovskites is provoking researchers to rethink this traditional picture, as the heterogeneity in several properties within these materials occurs on a series of length scales. Perovskites are typically fabricated crudely through simple processing techniques, which leads to large local fluctuations in defect density, lattice structure, chemistry and bandgap that appear on short length scales (<100 nm) and across long ranges (>10 μm). Despite these variable and complex non-uniformities, perovskites maintain exceptional device efficiencies and are, as of 2018, the best-performing polycrystalline thin-film solar cell material. In this Review, we highlight the multiple layers of heterogeneity ascertained using high-spatial-resolution methods that provide access to the relevant length scales. We discuss the impact that the optoelectronic variations have on halide perovskite devices, including the prospect that it is this very disorder that leads to their remarkable power-conversion efficiencies.

传统上，具有高晶格结构和低缺陷浓度的材料被认为是高性能光电器件必不可少的。但是，基于卤化钙钛矿的高效设备的出现正促使研究人员重新思考这一传统情况，因为这些材料中某些特性的异质性是在一系列长度尺度上发生的。钙钛矿通常通过简单的加工技术进行粗加工，从而导致缺陷密度，晶格结构，化学性质和能带隙的较大局部波动，这些波动出现在短长度范围（<100 nm）和长距离范围（> 10μm）上。尽管存在这些可变且复杂的不均匀性，但钙钛矿仍保持了出色的设备效率，截至2018年，性能最好的多晶薄膜太阳能电池材料。在这篇综述中，我们重点介绍了使用高空间分辨率方法确定的多层异质性，这些方法可提供对相关长度范围的访问。我们讨论了光电变化对卤化物钙钛矿器件的影响，包括这种无序现象导致其卓越的功率转换效率的前景。