An efficient perovskite solar cell (PSC) has the following characteristics: (1) large perovskite grain size; (2) small ion migration; (3) low defect density states. Here, benzoic acid was employed as an additive to a perovskite solution to improve the thin film quality. Surprisingly, 1.0%-BA can implement all of these features. Therefore, the power conversion efficiency (PCE) of the champion PSC is 18.05%, which is superior to that of the control device (15.42%). In addition, BA-doped PSC kept 86% of its primary PCE after 30 days (RH: 35%), but the control device only retained 75% under the same conditions. The improvement of its stability is because of the inhibition of the cation migration of perovskite by the addition of BA and the passivation of perovskite defects. The results can acquire a better understanding of the potential applications of small organic molecules in improving the PCE and stability of PSC devices.

中文翻译：

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苯甲酸抑制本征离子迁移，实现高效稳定的钙钛矿太阳能电池

高效的钙钛矿太阳能电池（PSC）具有以下特点：（1）钙钛矿晶粒尺寸大； (2)离子迁移小； (3)低缺陷密度态。在这里，苯甲酸被用作钙钛矿溶液的添加剂，以提高薄膜质量。令人惊讶的是，1.0%-BA 可以实现所有这些功能。因此，冠军PSC的功率转换效率（PCE）为18.05%，优于控制器件（15.42%）。此外，BA掺杂的PSC在30天后保留了86%的主要PCE（相对湿度：35%），但对照装置在相同条件下仅保留了75%。其稳定性的提高是由于BA的添加抑制了钙钛矿的阳离子迁移以及钙钛矿缺陷的钝化。研究结果可以更好地了解有机小分子在提高 PSC 器件的 PCE 和稳定性方面的潜在应用。