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 the 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 the 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 groups can create numerous hydrogen bonds with [PbI₆]⁴⁻ to dampen complex intermediate phases and facilitate directional crystallization of the 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 protocols, 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 °C). Encouragingly, the PhDFA-based solar module, featuring an active area of 642 cm², achieves a notable efficiency of 18.20%.