Multiple-Noncovalent-Interaction-Stabilized Layered Dion–Jacobson Perovskite for Efficient Solar Cells

Two-dimensional Dion–Jacobson
(DJ) perovskites have shown
improved structure stability in comparison with Ruddlesden–Popper
(RP) perovskites. However, the mechanism behind the improved stability
is still largely unexplored. Here a multifluorinated aromatic spacer,
namely, 4F-PhDMA, has been successfully developed for 2D DJ perovskites.
It is found that the 2D DJ perovskite with a 4F-PhDMA spacer exhibits
a high dissociation energy due to the multiple noncovalent interactions.
The optimized 2D DJ device based on the 4F-PhDMA spacer (n = 4) exhibits a champion efficiency of 16.62% with much improved
light and thermal stability. This efficiency is much higher than that
of the control device using an unfluorinated spacer (n = 4, PCE = 10.11%) and is among the highest efficiencies in aromatic-spacer-based
2D DJ perovskite solar cells (PSCs). Our work highlights the importance
of incorporating multiple noncovalent interactions in the 2D DJ perovskite
by employing a multifluorinated aromatic spacer to achieve DJ PSCs
with both high efficiency and high stability.