The performance of perovskite solar cells is sensitive to detrimental defects, which are prone to accumulate at the interfaces and grain boundaries of bulk perovskite films. Defect passivation at each region will lead to reduced trap density and thus less nonradiative recombination loss. However, it is challenging to passivate defects at both the grain boundaries and the bottom charge transport layer/perovskite interface, mainly due to the solvent incompatibility and complexity in perovskite formation. Here SnO₂‐KCl composite electron transport layer (ETL) is utilized in planar perovskite solar cells to simultaneously passivate the defects at the ETL/perovskite interface and the grain boundaries of perovskite film. The K and Cl ions at the ETL/perovskite interface passivate the ETL/perovskite contact. Meanwhile, K ions from the ETL can diffuse through the perovskite film and passivate the grain boundaries. An enhancement of open‐circuit voltage from 1.077 to 1.137 V and a corresponding power conversion efficiency increasing from 20.2% to 22.2% are achieved for the devices using SnO₂‐KCl composite ETL. The composite ETL strategy reported herein provides an avenue for defect passivation to further increase the efficiency of perovskite solar cells.

中文翻译：

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使用SnO2-KCl复合电子传输层的平面钙钛矿太阳能电池的同时接触和晶界钝化

钙钛矿太阳能电池的性能对有害缺陷敏感，这些缺陷易于累积在整体钙钛矿薄膜的界面和晶界处。每个区域的缺陷钝化将导致陷阱密度降低，从而减少非辐射重组损失。然而，主要由于溶剂的不相容性和钙钛矿形成的复杂性，在晶界和底部电荷传输层/钙钛矿的界面上钝化缺陷都是具有挑战性的。在这里SnO ₂‐KCl复合电子传输层（ETL）用于平面钙钛矿太阳能电池中，可同时钝化ETL /钙钛矿界面和钙钛矿薄膜晶界处的缺陷。ETL /钙钛矿界面处的K和Cl离子钝化ETL /钙钛矿接触。同时，来自ETL的K离子可以扩散穿过钙钛矿薄膜并钝化晶界。使用SnO ₂ -KCl复合ETL的器件可将开路电压从1.077 V提高到1.137 V，并将相应的功率转换效率从20.2％提高到22.2％。本文报道的复合ETL策略为缺陷钝化提供了一种途径，以进一步提高钙钛矿太阳能电池的效率。