Managing interfacial properties of planar perovskite solar cells using Y 3 N@C 80 endohedral metallofullerene

Fullerene derivatives have a wide range of applications in perovskite solar cells (PSCs), such as electron transport layers (ETLs), interfacial modifiers, and additives. However, there have been few studies of the use of endohedral metallofullerenes (EMFs) to improve the performance of PSCs. Here, a novel EMF (Y 3 N@C 80 ) was synthesized and used as an interfacial modifier in PSC devices based on a SnO 2 ETL. Energy level mismatches and detrimental carrier recombination have been observed in devices with a pristine SnO2 ETL, but these issues are alleviated with the assistance of Y 3 N@C 80 . A significant increase in open-circuit voltage from 1.106 V (SnO 2 ) to 1.14 V (SnO 2 -Y 3 N@C 80 ), an increase in power conversion efficiency from 20.59% to 21.66%, and a marked reduction in hysteresis were observed, which were attributed to the more suitable conduction band energy levels and more effective electron extraction at the SnO 2 -Y 3 N@C 80 /perovskite interface. In addition, the stability of the target devices was improved, which may be due to the hydrophobicity of Y 3 N@C 80 and a reduction in trap states.