From the perspective of the device structure of perovskite solar cells (PSCs), the electron transport layer is one of the essential components and plays a significant role in suppressing carrier recombination. Furthermore, its decisiveness is related to the quality of perovskite film, the rapid interface carrier extraction, and the bandgap alignment. However, the deficiency of the semiconductor oxides based electron transport materials, especially for most studied TiO₂, is that their carrier mobility is one to three orders of magnitude lower than the most commonly used hole transport materials, leading to an imbalanced carrier flux and unpredicted hysteresis. Doping new ions are the most effective ways to improve electron mobility and tune the bandgap, while the fundamental mechanism of doping in the majority of cases are still lacking. Herein, the doping effect on semiconductor oxides is reviewed and emphasized by classifying the doping ions according to the critical factors of lattice optimization, a carrier transporting improvement, and interface modification. This review is the first systematic summary of the ion doping characteristics in oxide electron transport layers of PSCs. Finally, the implementation of doping ions in electron transport materials is briefly discussed for further enhancing the photovoltaic performance of PSCs.

中文翻译：

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钙钛矿太阳能电池应用中基于半导体氧化物的电子传输材料中的掺杂

从钙钛矿太阳能电池（PSC）的器件结构的角度来看，电子传输层是必不可少的组件之一，并且在抑制载流子复合方面起着重要作用。此外，它的决定性与钙钛矿薄膜的质量，快速的界面载流子提取和带隙取向有关。然而，基于半导体氧化物的电子传输材料的不足，特别是对于大多数研究的TiO ₂这是因为它们的载流子迁移率比最常用的空穴传输材料低一到三个数量级，从而导致载流子流量不平衡和不可预测的磁滞现象。掺杂新离子是提高电子迁移率和调节带隙的最有效方法，而在大多数情况下仍缺乏掺杂的基本机制。在此，通过根据晶格最优化，载流子传输改进和界面改性的关键因素对掺杂离子进行分类来回顾和强调对半导体氧化物的掺杂效果。这篇综述是PSC氧化物电子传输层中离子掺杂特性的首次系统总结。最后，