Theoretical investigations on crystal crosslinking in perovskite solar cells

Molecule based crosslinking agents have been applied in perovskite solar cells to produce perovskites with better crystal quality, resulting in excellent optoelectronic performance of the solar cells. Nevertheless, the mechanisms of the crystal formation process mediated by the crosslinking agents have not been studied, especially in the cases where some molecules serve as good crosslinking agents, while others with very similar molecular structures do not. In this study, we theoretically investigate the structures and properties of the crosslinking agents and provide insights into the mechanisms of the crosslinking agent-mediated perovskite crystal formation. We demonstrate that the chain lengths in the crosslinking agents are of vital importance for the crystal formation in perovskite solar cells. This study helps in the understanding of the molecule based surface/interface engineering approach of perovskite solar cells.