Perovskite solar cells (PSCs) are emerging among the photovoltaic (PV) technologies due to their high power conversion efficiency (PCE) in combination with potentially low cost manufacturing processing. In this contribution, the fabrication of efficient planar n‐i‐p PSCs by the modification of the electron transport layer (ETL) adopted as n‐type contact is demonstrated. Specifically, a fluorine‐based plasma treatment prior to perovskite deposition leads to surface fluorination of the TiO₂ ETL. The presence of fluorine on the TiO₂ surface drastically improves the adhesion between the ALD layer and the methylammonium lead iodide perovskite film, and leads to a more favourable energy band alignment, accompanied by a faster electron carrier extraction at the interface. As consequence of surface fluorination, we observe a significant reduction in the current density‐voltage curve hysteresis with respect to the ALD based reference sample, as well as a remarkable improvement in power conversion efficiency from 4% up to a stable 14.8%.

中文翻译：

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平面型钙钛矿太阳能电池用ALD TiO2电子传输层的表面氟化

钙钛矿太阳能电池（PSC）由于其高功率转换效率（PCE）和潜在的低成本制造工艺而在光伏（PV）技术中崭露头角。在此贡献中，展示了通过修改用作n型接触的电子传输层（ETL）来制造有效的平面n-i-p PSC。具体而言，在钙钛矿沉积之前进行基于氟的等离子体处理会导致TiO ₂ ETL的表面氟化。TiO ₂上存在氟表面极大地改善了ALD层与甲基铵碘化铅钙钛矿薄膜之间的附着力，并导致了更有利的能带排列，并伴随着界面处更快的电子载流子提取。表面氟化的结果是，相对于基于ALD的参考样品，我们观察到电流密度-电压曲线的磁滞明显降低，并且功率转换效率从4％显着提高到了14.8％的稳定水平。