Air‐processed perovskite solar cells (PSCs) allay the need for costly fabrication in a controlled atmosphere but currently suffer from disadvantages in power conversion efficiency (PCE) and device stability. Herein, the systematic investigation into CH₃NH₃PbI_3–xCl_x prepared with an antisolvent‐assisted process in a relative humidity of 40 ± 5% is reported, using cesium‐containing aqueous solutions of various strengths. Diffractometry and microscopy reveal how grain sizes vary among the samples, suggesting an optimum concentration for grain size. Those films are fabricated in air into solar cells, and their electrochemical impedance and current–voltage characteristics under light are measured. The films demonstrating optimum strength achieve PCEs of up to 16.6%, compared with the maximum of 14.4% achieved by untreated films. The air‐processed films also exhibit mitigated hysteresis, with indices decreasing to 0.021. Photoluminescence characterization reveals reduced defect densities in Cs‐doped materials and, together with photoelectron spectroscopy, suggests an upward shift in energy bands. Such changes explain the improvement in photovoltaic performance. Stability tests on unencapsulated cells over 14 days show that those made from the perovskite with optimum Cs‐doping degrade slowest, with their conversion efficiencies falling by <10% every 100 h. Our findings may contribute to the low‐cost commercialization of PSCs.

中文翻译：

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空气倒钙钛矿太阳能电池中掺铯的水前体的协同效益

空气处理的钙钛矿太阳能电池（PSC）消除了在可控气氛中进行昂贵制造的需求，但目前存在功率转换效率（PCE）和设备稳定性方面的缺点。在这里，对CH ₃ NH ₃ PbI _{3– x} Cl _x的系统研究据报道，使用各种浓度的含铯水溶液，可在40±5％的相对湿度下通过反溶剂辅助工艺制备。衍射和显微镜检查揭示了样品之间晶粒尺寸如何变化，表明晶粒尺寸的最佳浓度。这些薄膜在空气中制成太阳能电池，并在光下测量其电化学阻抗和电流-电压特性。表现出最佳强度的薄膜可实现高达16.6％的PCE，而未经处理的薄膜最高可达到14.4％。空气处理过的薄膜还表现出滞后现象，折射率降低至0.021。光致发光特性表明掺杂Cs的材料中的缺陷密度降低，并且与光电子能谱一起表明能带向上移动。这种变化说明了光伏性能的提高。对未封装细胞进行14天以上的稳定性测试表明，由钙钛矿和最佳Cs掺杂制成的那些电池降解最慢，其转换效率每100小时下降<10％。我们的发现可能有助于PSC的低成本商业化。