Diammonium Molecular Configuration-Induced Regulation of Crystal Orientation and Carrier Dynamics for Highly Efficient and Stable 2D/3D Perovskite Solar Cells.

The effects from the molecular configuration of diammonium spacer cations on 2D/3D perovskite properties are still unclear. Here, we investigated systematically the mechanism of molecular configuration-induced regulation of crystallization kinetic and carrier dynamics by employing various diammonium molecules to construct Dion-Jacobson (DJ)-type 2D/3D perovskites to further facilitating the photovoltaic performance. The minimum average Pb-I-Pb angle leads to the smallest octahedral tilting of [PbX ] lattice in optimal diammonium molecule-incorporated DJ-type 2D/3D perovskite, which enables suitable binding energy and hydrogen-bonding between spacer cations and inorganic [PbX ] cages, thus contributing to the formation of high-quality perovskite film with vertical crystal orientation, mitigatory lattice distortion and efficient carrier transportation. As a consequence, a dramatically improved device efficiency of 22.68 % is achieved with excellent moisture stability.