In Situ Supramolecular Depolymerization Enables Bifunctional Buried‐Interface Passivation in Inverted Perovskite Solar Cells

Introducing multidentate organic passivators has emerged as an effective strategy for defect passivation at the buried interface of inverted perovskite solar cells (PSCs). However, the active polar functional groups within these passivators are prone to supramolecular polymerization, which compromises passivation effectiveness. Herein, a supramolecular depolymerization strategy synergistically driven by thermal annealing and heteromolecular interactions is proposed. This approach enables the in situ depolymerization of the Zaltoprofen (Za) supramolecular structures introduced at the buried interface. The resulting depolymerized Za molecules are effectively anchored onto the underlying hole transport layer (HTL), while their molecular orientation is optimized to expose Lewis base coordination sites toward the perovskite layer. Consequently, enhanced coordination interactions with undercoordinated Pb 2+ are achieved, leading to more effective interfacial defect passivation and improved charge extraction. As a result, inverted PSCs based on a 1.57 eV bandgap perovskite exhibit a significantly improved power conversion efficiency ( PCE ), increasing from 24.05% to 25.61%. Moreover, the devices treated with this strategy demonstrate substantially enhanced operational stability compared with the pristine devices. This work provides a simple and effective strategy for activating supramolecular passivators and maximizing their defect‐passivation capability in high‐efficiency inverted PSCs.