In the past few years, inorganic perovskite compounds including CsPbI₃, CsSnI₃ and others using as light absorbers in emerging solar cells have become one of the most promising research directions to solve the issue of stability faced by their organic–inorganic hybrid halide counterparts. So far, the reported power conversion efficiency of laboratory produced CsPbI₃-based perovskite solar cells has exceeded 19%. However, a spontaneous transition of black α-CsPbI₃ to non-photosensitive yellow δ-CsPbI₃ at the room temperature is considered as a serious obstacle of its further application for this material. The phase transition can be induced by strain correlated with the interaction between the PbI₆ octahedron and the Cs⁺ cation. Therefore, several strategies have been proposed to enhance phase stability of inorganic perovskites and thus the corresponding photovoltaic devices’ performance, such as doping engineering, additives, and dimensionality engineering. We notice that strain is unavoidable in solution-processable perovskite devices of layered structures and, thus, may play an important influence on the macroscopic photovoltaic parameters via microscopic effect on crystalline lattice. In this review, we mainly focus on the effect of strain on phase stability of CsPbI₃. In this review, we first introduced the type and distribution of strains in inorganic perovskite materials and summarized the causes for this along with common characterization methods. Then we discussed the origin for instability and contribution of strain to phase stability of CsPbI₃. The effects of strain on bandgap and carrier transport of CsPbI₃ were also analyzed. We further outlooked the application prospects and challenges of strain engineering onto CsPbI₃ perovskite materials for the purpose of photovoltaic application.

在过去的几年中，无机钙钛矿化合物（包括CsPbI ₃，CsSnI ₃等）在新兴太阳能电池中用作光吸收剂，已成为解决有机-无机杂化卤化物对应物所面临的稳定性问题的最有希望的研究方向之一。到目前为止，报告的实验室生产的基于CsPbI ₃的钙钛矿太阳能电池的功率转换效率已超过19％。但是，黑色α - CsPbI ₃自发转变为非感光黄色δ - CsPbI ₃在室温下加热被认为是进一步将该材料应用的严重障碍。可以通过与PbI ₆八面体和Cs ⁺阳离子之间的相互作用相关的应变来诱导相变。因此，已经提出了几种策略来增强无机钙钛矿的相稳定性，从而增强相应的光电器件的性能，例如掺杂工程，添加剂和尺寸工程。我们注意到，在层状结构的固溶钙钛矿器件中应变是不可避免的，因此，通过对晶格的微观影响，应变可能会对宏观光伏参数产生重要影响。在这篇综述中，我们主要关注应变对CsPbI相稳定性的影响。₃。在本文中，我们首先介绍了无机钙钛矿材料中菌株的类型和分布，并总结了其原因以及常见的表征方法。然后，我们讨论了不稳定性的起源以及应变对CsPbI ₃相稳定性的影响。还分析了应变对CsPbI ₃带隙和载流子传输的影响。我们进一步展望了用于光伏应用的CsPbI ₃钙钛矿材料在应变工程上的应用前景和挑战。