Although [6,6]-phenyl-C₆₁-butyric acid methyl ester (PC₆₁BM) has been widely used as electron transport layer (ETL) for inverted perovskite solar cells (PeSCs), it still remains to be improved. Herein, we report that amphoteric imidazole (IZ) and benzimidazole (BIZ) can act as effective and multifunctional dopants for PC₆₁BM-based ETL. The resultant MAPbI₃-xCl₃-based PeSCs outperform the devices with pristine PC₆₁BM ETL with power conversion efficiency (PCE) significantly improved from 14.38% to 15.62/16.47%. Detailed mechanism studies demonstrate that IZ and BIZ-doping cause remarkable reduction of ETL surface roughness and significant increase in electrical conductivity of ETL, both of which facilitate the electron transport from perovskite (PVK) and Ag cathode. More importantly, IZ and BIZ as dopants may passivate both Lewis-acid and Lewis-base type defects on the PVK surface due to their amphoteric nature. DFT computations further reveal that BIZ is a better Lewis-base and Lewis-acid than IZ due to its larger π-conjugation, which thus makes it a superior dopant over IZ. In addition, the PeSCs with PC₆₁BM:BIZ based ETL display enhanced device stability by retarding the I⁻ anion migration from PVK to Ag cathode.

尽管[6，6]-苯基-C _61-丁酸甲酯（PC ₆₁ BM）已被广泛用作反钙钛矿太阳能电池（PeSCs）的电子传输层（ETL），但仍有待改进。本文中，我们报道了两性咪唑（IZ）和苯并咪唑（BIZ）可以作为基于PC ₆₁ BM的ETL的有效多功能掺杂剂。所得的基于MAPbI ₃ -xCl ₃的PeSC优于具有原始PC ₆₁的设备具有功率转换效率（PCE）的BM ETL从14.38％显着提高到15.62 / 16.47％。详细的机理研究表明，IZ和BIZ掺杂会显着降低ETL表面粗糙度，并显着提高ETL的电导率，这两者都促进了钙钛矿（PVK）和Ag阴极的电子传输。更重要的是，由于IZ和BIZ作为掺杂剂，由于其两性性质，它们可以钝化PVK表面上的路易斯酸和路易斯碱型缺陷。DFT计算进一步表明，由于BIZ具有更大的π共轭，因此BIZ比IZ具有更好的Lewis碱和Lewis酸，因此它比IZ具有更好的掺杂剂。此外，PC的PeSCs ₆₁ BM：BIZ基于ETL显示通过延迟予增强的器件稳定性^- 阴离子从PVK迁移到Ag阴极。