The defect passivation of perovskite films is an efficacious way to further boost the power conversion efficiency (PCE) and long-term stability of perovskite solar cells (PSCs). In this work, ionic liquids (ILs) of 1-butyl-2,3-dimethylimidazolium chloride ([BMMIm]Cl) are used as a modification layer in perovskite films in carbon-based CsPbBr3 PSCs without a hole-transporting material (HTM) for passivating the surface defects. The preliminary results demonstrate that the [BMMIm]Cl modifier passivates the surface defects of the perovskite film and reduces the valence band of perovskite close to the work function of the carbon electrode, which causes a remarkably inhibited nonradiative and radiative charge recombination, improved energy-level matching, and decreased energy loss. After optimization, a champion efficiency of 9.92% with a Voc as high as 1.61 V is achieved for the [BMMIm]Cl tailored carbon-based CsPbBr3 PSC without HTM, which is improved by 61.3% in comparison with 6.15% for the control device. Furthermore, the encapsulation-free PSC presents good long-term stability after storage in an air atmosphere with 70% RH at 20 °C or 0% RH at 80 °C as well as under continuous illumination conditions for 30 days. The significantly improved PCE and stability in high humidity or temperature suggest that the perovskite passivation by ILs is an effective strategy for fabricating high-PCE and stable PSCs.

中文翻译：

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咪唑鎓离子液体与高效稳定CsPbBr3钙钛矿太阳能电池的界面工程。

钙钛矿薄膜的缺陷钝化是一种进一步提高钙钛矿太阳能电池（PSC）的功率转换效率（PCE）和长期稳定性的有效方法。在这项工作中，将1-丁基-2,3-二甲基咪唑鎓氯化物（[BMMIm] Cl）的离子液体（IL）用作不含空穴传输材料（HTM）的碳基CsPbBr3 PSC中钙钛矿膜的改性层。用于钝化表面缺陷。初步结果表明，[BMMIm] Cl改性剂可钝化钙钛矿膜的表面缺陷，并降低钙钛矿的价带，使其接近碳电极的功函数，从而显着抑制了非辐射和辐射电荷的复合，改善了能量-电平匹配，减少能量损失。经过优化，冠军效率为9。不使用HTM的[BMMIm] Cl定制碳基CsPbBr3 PSC达到92％的Voc高达1.61 V，与控制设备的6.15％相比，提高了61.3％。此外，无封装的PSC在20°C的RH为70％或80°C的RH为0％的大气中以及连续照明条件下存放30天后，具有良好的长期稳定性。PCE的显着改善和在高湿度或高温下的稳定性表明，离子液体对钙钛矿的钝化作用是制造高PCE和稳定PSC的有效策略。不含封装的PSC在20％C的相对湿度为70％或80°C的相对湿度为0％的空气环境中以及在连续照明条件下存放30天后，具有良好的长期稳定性。PCE的显着改善和在高湿度或高温下的稳定性表明，离子液体对钙钛矿的钝化作用是制造高PCE和稳定PSC的有效策略。不含封装的PSC在20％C的相对湿度为70％或80°C的相对湿度为0％的空气环境中以及在连续照明条件下存放30天后，具有良好的长期稳定性。PCE的显着改善和在高湿度或高温下的稳定性表明，离子液体对钙钛矿的钝化作用是制造高PCE和稳定PSC的有效策略。