Amidino‐based additives show great potential in high‐performance perovskite solar cells (PSCs). However, the role of different functional groups in amidino‐based additives have not been well elucidated. Herein, two multifunctional amidino additives 4‐amidinobenzoic acid hydrochloride (ABAc) and 4‐amidinobenzamide hydrochloride (ABAm) are employed to improve the film quality of formamidinium lead iodide (FAPbI3) perovskites. Compared with ABAc, the amide group imparts ABAm with larger dipole moment and thus stronger interactions with the perovskite components, i.e., the hydrogen bonds between N…H and I− anion and coordination bonds between C = O and Pb2+ cation. It strengthens the passivation effect of iodine vacancy defect and slows down the crystallization process of α‐FAPbI3, resulting in the significantly reduced non‐radiative recombination, long carrier lifetime of 1.7 µs, uniformly large crystalline grains, and enhances hydrophobicity. Profiting from the improved film quality, the ABAm‐treated PSC achieves a high efficiency of 24.60%, and maintains 93% of the initial efficiency after storage in ambient environment for 1200 hours. This work provides new insights for rational design of multifunctional additives regarding of defect passivation and crystallization control toward highly efficient and stable PSCs.

中文翻译：

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多功能脒基添加剂高效稳定甲脒碘化铅太阳能电池的缺陷钝化和结晶调控


脒基添加剂在高性能钙钛矿太阳能电池（PSC）中显示出巨大潜力。然而，不同官能团在脒基添加剂中的作用尚未得到很好的阐明。在此，采用两种多功能脒基添加剂4-脒基苯甲酸盐酸盐（ABAc）和4-脒基苯甲酰胺盐酸盐（ABAm）来提高甲脒碘化铅（FAPbI3）钙钛矿的薄膜质量。与ABAc相比，酰胺基团赋予ABAm更大的偶极矩，从而与钙钛矿组分产生更强的相互作用，即N…H和I−阴离子之间的氢键以及C=O和Pb2+阳离子之间的配位键。它增强了碘空位缺陷的钝化作用，减慢了α-FAPbI3的结晶过程，导致非辐射复合显着减少，载流子寿命长达1.7 µs，晶粒均匀大，疏水性增强。受益于薄膜质量的提高，经过ABAm处理的PSC实现了24.60%的高效率，并且在环境环境中储存1200小时后仍保持初始效率的93%。这项工作为合理设计多功能添加剂的缺陷钝化和结晶控制以实现高效稳定的PSC提供了新的见解。