Rational design of spacer cations toward efficient and stable 2D/3D heterostructure perovskite solar cells

The integration of 2D and 3D perovskite materials can enhance the stability and efficiency of perovskite solar cells. This study examines the impact of modifying common organic spacers-2AI, PEA, and FPEA- with formamidinium (FA), guanidinium (GA), and methylenediammonium (MDA) cations on the interface between 2D and 3D layers in FAPbI3 perovskite materials. Structural analysis, electrostatic mapping, and energy calculations reveal that GA modification strengthens binding but destabilizes stacking, while MDA modification improves stability and charge transfer. These findings offer valuable insights into optimizing organic spacer modifications for 2D/3D perovskite solar cell performance.