Molecular Bridging Enables Uniform and Solvent‐Resilient Buried Contacts for Efficient and Stable Perovskite/TOPCon Tandem Solar Cells

ABSTRACT

Self‐assembled monolayers (SAMs) enable high‐performance inverted perovskite solar cells and perovskite/silicon tandem solar cells, but polar solvents can partially disrupt preformed SAMs and produce nonuniform buried contacts, a challenge amplified on silicon substrates. Here, 3‐(9H‐carbazol‐9‐yl)propan‐1‐aminium iodide (CzPA) is introduced as a molecular bridge at the SAM/perovskite buried interface. The carbazole unit promotes π–π interactions with the SAM, improving monolayer retention during solvent exposure, while the terminal ammonium group interacts with iodide‐containing precursor species to regulate interfacial nucleation. Furthermore, the iodide ions can effectively passivate the iodide vacancies at the buried interface. The reconstructed interface accelerates early‐stage nucleation, promotes orientationally ordered crystal growth, and reduces residual tensile stress, thereby yielding a more p‐type heterojunction and effectively suppressing non‐radiative recombination. CzPA‐modified wide‐bandgap inverted single‐junction cells deliver a PCE of 23.79%. Applied to perovskite/tunnel oxide passivating contact (TOPCon) tandems, this strategy improves perovskite continuity in pyramid valleys, enabling 1 cm ² devices with a PCE of 33.4%. Unencapsulated tandems retain 88% of their initial PCE after 800 h of one‐sun maximum‐power‐point tracking and 90% of their post‐burn‐in PCE after 737 h at 85°C, underscoring the robustness of the reconstructed buried interface.