Enhancing the Performance of Perovskite Solar Cells via the Functional Group Synergistic Effect in Interfacial Passivation Materials

Interfacial defects are considered to be a stumbling block in producing highly efficient perovskite solar cells (PSCs), so a more reasonable design is required for interfacial passivation materials (IPMs) to achieve further improvements in PSC performance. Here, we use fluorine atom (−F) and methoxy (−OCH3) functional groups to modify the same molecular fragment, obtaining three kinds of IPMs named YZ-301, YZ-302, and YZ-303, respectively. Through the subtle combination of −F and −OCH3, the fragment in YZ-302 exhibits an enhanced electronegativity, rendering the correlative IPM with a stronger interaction with the perovskite layer. As a result, YZ-302 shows the best defect passivation and hole transport effect at the interface, and the PSC based on YZ-302 treatment achieves the best efficiency approaching 24%, which is better than the reference and devices with other IPMs, and it also has excellent device stability.