Titanium oxide (TiO₂) is commonly used as an electron transport layer (ETL) of regular-structure perovskite solar cells (PSCs); however, it suffers from inherent drawbacks such as low electron mobility and a high density of trap states. Modifying the surface chemistry of TiO₂ has proved facile and efficient in enhancing key electron-transport properties, thereby improving device performance. In this review, we summarize recent progress on the surface modification of TiO₂ in planar PSCs. The functions of different modifiers in improving device performance are elucidated, revealing the influence of modifier chemical and electronic structure on the properties of TiO₂. This offers new opportunities to exploit novel materials for modifying TiO₂ toward high-efficiency PSCs.

钛白粉（TiO ₂）通常用作规则结构钙钛矿太阳能电池（PSC）的电子传输层（ETL）。然而，它具有诸如电子迁移率低和陷阱态密度高之类的固有缺陷。事实证明，改变TiO ₂的表面化学性质既容易又有效地增强了关键的电子传输性能，从而改善了器件性能。在这篇综述中，我们总结了平面型PSC中TiO ₂表面改性的最新进展。阐明了不同改性剂在改善器件性能中的功能，揭示了改性剂的化学和电子结构对TiO ₂性能的影响。这为开发新型材料以将TiO ₂改性为高效PSC提供了新的机会。