Double Amidino-Mediated Multiple Hydrogen-Bonded Dion-Jacobson Perovskites Enable Oriented Crystallization for Efficient Inverted FAPbI3 Solar Cells and Modules (642 cm²)

Abstract

Two-dimensional (2D) Ruddlesden-Popper (RP) perovskites are utilized to boost stability of FAPbI3 perovskite solar cells (PSCs), but their effectiveness is constrained by van der Waals gaps (VDWGs). Although Dion-Jacobson (DJ) perovskites can eliminate VDWGs, the limited number of hydrogen bonds formed by conventional double amine-based spacers with [PbI6]4- is not conducive to long-term structural and phase stability of FAPbI3. Herein, a double amidino-based spacer of benzdiamidinium (PhDFA) is employed to develop DJ 2D/3D FAPbI3-based PSCs. PhDFA with double amidino can create numerous hydrogen bonds with [PbI6]4- to dampen complex intermediate phases and facilitate directional crystallization of δ to α phase. Notably, the multi-hydrogen bond network constructed by PhDFA can effectively modulate crystal orientation, reduce residual strain, and passivate trap states. The resultant perovskite photovoltaics demonstrate exceptional efficiencies of 26.10% (0.10 cm²) (certified 25.72%) and 24.81% (1.01 cm²), marking the highest efficiencies reported for DJ 2D/3D PSCs to date. Based on ISOS protocol, the unencapsulated devices exhibit a T86 value over 8000 h under environmental conditions (RH = 30-40%) and a T98 value exceeding 1220 h during operational stability testing (T = 60 ℃). Encouragingly, the PhDFA-based solar module, featuring an active area of 642 cm², achieves a notable efficiency of 18.20%.