VOC of Inverted Perovskite Solar Cells Based on N‐Doped PCBM Exceeds 1.2 V: Interface Energy Alignment and Synergistic Passivation

Abstract Phenyl‐C61‐butyric acid methyl ester (PCBM) remains the most commonly used electron transport layer in inverted perovskite solar cells (IPSCs). However, its insufficient electrical properties and passivation ability limit the device's performance. In this study, it is demonstrated that introducing an appropriate amount of n‐type polymer N2200 into the PCBM can simultaneously enhance the electrical properties of PCBM and passivate the defects distributed on perovskite surface. This modification of PCBM leads to improved band alignment and enhanced electron mobility. Simultaneously, N2200 polymer contains electron donors such as O, S involved in passivating uncoordinated Pb 2+ defects. The PCBM@N2200‐based IPSCs exhibit an enhanced open‐circuit voltage ( V OC ) of 1.20 V with the minimum 0.36 V voltage loss and reach the champion power conversion efficiency (PCE) of 24.53% (certified PCE is 24.05%) with narrow distribution. Impressively, the corresponding module achieves an efficiency of 20.30% (11.19 cm 2 ). Moreover, the PCBM@N2200‐based IPSCs maintain 96% of their initial efficiency after operating at the maximum power point for 500 h, thanks to the interfacial passivation, improved uniformity, and increased hydrophobicity resulting from N2200 doping.