On the surface and grain boundary of perovskite films there are large quantities defects, which leads to photogenerated carrier nonradiative recombination and degrades the performance of the perovskite solar cells (PSCs). Surface passivation can suppress the detrimental effects of defect and improve the performance of PSCs. Here, an organic molecule, 4-chloro-1,8-naphthalic anhydride (ALS), is adopted to passivate the defects on the surface and grain boundary of (FAPbI₃)_0.95(MAPbBr₃)_0.05 perovskite films. The oxygen of carbonyl group in the ALS provides lone pair electron to the undercoordinated Pb²⁺ and passivated this defect. The ALS passivated perovskite films have lower trap state density and longer carrier lifetime. As a result, the photoelectric conversion efficiency (PCE) of the PSCs was improved from 21.52% to 23.72%. Furthermore, the ALS passivated PSC show good stability, and it could maintain 88% of its initial efficiency after 1200 h storage in ambient atmosphere without encapsulation.

中文翻译：

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4-氯-1,8-萘酸酐表面钝化提高钙钛矿太阳能电池的性能

钙钛矿薄膜的表面和晶界存在大量缺陷，导致光生载流子非辐射复合，降低钙钛矿太阳能电池（PSC）的性能。表面钝化可以抑制缺陷的不利影响并提高 PSC 的性能。在这里，采用有机分子 4-氯-1,8-萘酐 (ALS) 来钝化 (FAPbI ₃ ) _0.95 (MAPbBr ₃ ) _0.05钙钛矿薄膜表面和晶界上的缺陷。ALS中羰基的氧为配位不足的Pb ^{2+提供孤对电子}并钝化了这个缺陷。ALS 钝化钙钛矿薄膜具有较低的陷阱态密度和较长的载流子寿命。结果，PSC 的光电转换效率 (PCE) 从 21.52% 提高到 23.72%。此外，ALS 钝化的 PSC 表现出良好的稳定性，在没有封装的环境大气中储存 1200 小时后，它可以保持其初始效率的 88%。