2,2′,7,7′‐tetrakis‐(N,N‐di‐4‐methoxyphenylamino)‐9,9′‐spirobifluorene (spiro‐MeOTAD) hole transport material (HTM) is a milestone in the history of perovskite solar cells (PSCs). Proper choice of HTMs is key factor for efficient charge extraction and stability in solar cells. Spiro‐MeOTAD is proven to be the most suitable HTM for testing PSCs due to its facile implementation and high performance. Similarly, spiro‐MeOTAD is receiving attention in other applications other than in solar cells due to its desirable properties. However, spiro‐MeOTAD is under debate regarding the topics of cost‐performance, long‐term stability, degradation issues (induced by temperature, additives, film quality, and environmental conditions), coating technologies compatibility, reliance on additives, and hysteresis. In this review, the advent of spiro‐MeOTAD, and related aforementioned issues about spiro‐MeOTAD are discussed. In addition, spiro‐MeOTAD properties, alternative and new additives, other applications, and new HTMs that is comparable or outperforms spiro‐MeOTAD in PSCs are summarized. In the outlook, the future research directions based on reported results that warrant further investigations are outlined.

中文翻译：

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Spiro-MeOTAD空穴传输材料的最新进展及其在有机-无机卤化物钙钛矿太阳能电池中的应用

2,2'，7,7'-四（N，N-二-4-甲氧基苯基氨基）-9,9'-螺双芴（spiro-MeOTAD）空穴传输材料（HTM）是钙钛矿太阳能历史上的一个里程碑单元（PSC）。正确选择HTM是有效提取电荷和稳定太阳能电池的关键因素。由于Spiro-MeOTAD实施简便且性能卓越，因此被证明是最适合测试PSC的HTM。同样，spiro-MeOTAD由于其理想的性能而在除太阳能电池以外的其他应用中也受到关注。但是，关于成本性能，长期稳定性，降解问题（由温度，添加剂，薄膜质量和环境条件引起），涂层技术的兼容性，对添加剂的依赖以及磁滞现象等话题，spiro-MeOTAD仍在辩论中。在这篇评论中，spiro-MeOTAD的问世，以及与上述有关spiro-MeOTAD的相关问题进行了讨论。此外，总结了螺环-MeOTAD的性能，替代品和新添加剂，其他应用以及在PSC中具有可比性或优于螺环-MeOTAD的新HTM。展望中，概述了基于报告结果的未来研究方向，值得进一步研究。