The notoriously poor stability of organic–inorganic hybrid perovskite solar cells is a crucial issue restricting the commercial application of such burgeoning technology. Passivation of bulk perovskite absorber by fluorinated aromatic ammonium salt via low‐dimensional perovskites has been proved to be an effective way of improving stability and efficiency. Herein, the influence of fluorination position (ortho‐, meso‐, and para‐) on the aromatic moiety is studied in terms of their dipole moments and the ability to reduce defect density, extend carrier lifetimes, and assist charge transfer. In addition to the improved power conversion efficiency (PCE) from 19.17% to above 20%, the device treated with 2‐(o‐fluorophenyl)ethylamine iodide exhibits a remarkable open‐circuit voltage (V_OC) of 1.21 V. While the 2‐(p‐fluorophenyl)ethylamine iodide‐treated device shows only 1% loss of its initial value under ambient atmosphere (with RH of 10–30%) without encapsulation for 1440 h storage. The molecular structure of fluorinated aromatic cations plays multiple roles in passivating the interface of the perovskite device.

中文翻译：

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具有改善的VOC和稳定性的含氟芳香族阳离子辅助的平面结钙钛矿太阳能电池：氟化位置的作用

众所周知，有机-无机杂化钙钛矿太阳能电池的稳定性很差，这是限制这种新兴技术在商业上应用的关键问题。氟化芳族铵盐通过低维钙钛矿对大量钙钛矿吸收剂的钝化已被证明是提高稳定性和效率的有效方法。这里，氟化位置的影响（邻- ，中孔，和对- ）上的芳族部分在它们的偶极矩和减少的缺陷密度，延长载流子寿命，并协助电荷转移的能力方面进行了研究。除了将功率转换效率（PCE）从19.17％提高到20％以上之外，该设备还经过2-（o‐氟苯基）乙胺碘化物的开路电压（V _OC）为1.21 V.而经过2-（对氟苯基）乙胺碘化物处理的装置在环境大气下（相对湿度为RH）仅损失其初始值的1％。 10％到30％），而无需封装以存放1440小时。氟化芳族阳离子的分子结构在钝化钙钛矿装置的界面方面起着多种作用。