While self-assembled monolayer (SAM) materials show promise for interface engineering in perovskite solar cells, it is quite challenging to achieve an optimal balance between molecular packing density, charge transport efficiency, and defect passivation. To address this issue, researchers from Henan University, Southern University of Science and Technology and City University of Hong Kong have proposed a SAM material design strategy that synergizes flexible head groups with rigid linking groups.
Using (4-(diphenylamino)phenyl)phosphonic acid as a model molecule, compared to traditional materials such as (4-(9H-carbazol-9-yl)phenyl)phosphonic acid and (4-(diphenylamino)phenethyl)phosphonic acid, the material generated a high-quality perovskite layer. This design achieves superior energy level alignment, improved hole extraction, and enhanced charge transport efficiency, effectively reducing non-radiative recombination.
The team showed that the (4-(diphenylamino)phenyl)phosphonic acid-based device achieved a power conversion efficiency of 26.21% and 24.49% for small- (0.0715 cm2) and large-area (1 cm2), respectively.
This work presents an effective approach to SAM molecular design, providing a clear pathway for improving both the efficiency and long-term stability of perovskite solar cells through interface engineering.
