Effective Interface Defect Passivation via Employing 1-Methylbenzimidazole for Highly Efficient and Stable Perovskite Solar Cells

Although the power conversion efficiencies (PCEs) of perovskite solar cells (PSCs) have made great progress, the surface and interface defects still affect their PCE and stability and hinder the commercialization. To overcome this problem, 1-methylimidazole (1-MIm) and 1-methylbenzimidazole (1-MBIm) were used as the interfacial passivation agents to passivate the defects at surface and interface. The results indicated that, in contrast to 1-MIm, 1-MBIm displayed a stronger Lewis coordination interaction with the uncoordinated Pb2+ to reduce the non-radiative recombination and also effectively improved the charge transfer capacity of perovskite films due to its strong pi-pi conjugate interaction, resulting in the better photovoltaic performance. As a result, the PCE of the champion 1-MBIm PSC was improved from 19.48 (pristine) to 21.22 % with a dramatically enhanced open-circuit voltage (V-oc=1.15 V). More importantly, a significant improvement in long-term stability was achieved for 1-MBIm perovskite devices, which was attributed to the high-quality perovskite film caused by the strong passivation effect of 1-MBIm and the hydrogen bond with water molecules. The results offers an efficient and facile strategy by interface engineering to fabricate high-performance and stable PSCs for commercial application.

Automated summary

By utilizing 1-MIm and 1-MBIm as interfacial passivation agents, the performance and stability of perovskite solar cells have been significantly improved. The strong passivation effect of 1-MBIm and its interaction with water molecules contribute to the enhanced photovoltaic performance and long-term stability of the devices, offering an efficient strategy for commercial application.