Molecular bidirectional hydrogen-bonding bridge interface enables the fabrication of 27.5% efficient inverted perovskite solar cells and 17.5% flexible modules

Abstract

Inverted perovskite solar cells have approached their theoretical efficiency ceiling, yet the electronically fragile perovskite/C60 heterointerface remains a major impediment to further suppressing voltage loss, ion migration, and long-term operational degradation. Here, we report a molecular bidirectional hydrogen-bonding bridge interface that transforms the conventional perovskite/C60 contact into a chemically coupled and electronically benign heterojunction. The rationally designed thifensulfuron-methyl (TFSM) molecule simultaneously interacts with FA+/I−/Pb2+ species in the perovskite through multidentate hydrogen bonding and coordination, while establishing N–H⋯π interactions with C60. This supramolecular interfacial architecture immobilizes volatile organic cations, passivates undercoordinated lead/halide defects, reinforces interfacial dipole modulation, and accelerates electron extraction. Consequently, non-radiative recombination and interfacial energetic disorder are markedly mitigated. The resulting inverted devices achieve a power conversion efficiency of 27.49% (certified 27.42%), together with substantially enhanced thermal, moisture, and operational stability. More importantly, this strategy is compatible with scalable fabrication, enabling flexible perovskite modules with an efficiency of 17.5%. This work establishes bidirectional molecular bridging as a powerful design principle for efficient and scalable perovskite photovoltaics.