Synergistic Molecular Locking Through Sodium‐Integrated Cross‐Linkable Scaffold Enables Durable Perovskite Solar Cells and Modules

ABSTRACT The primary challenge in commercializing perovskite solar cells (PSCs) mainly stems from undesired non‐radiative recombination loss and defect‐mediated migration of halide perovskite materials. Herein, we propose a synergistic stabilization strategy integrating in situ polymerization with sodium interstitial doping to concurrently regulate crystallization kinetics and suppress ion migration. The cross‐linked scaffold formed by sodium thioctate (TANA) templates high‐quality perovskite growth through retarded crystallization and suppressed nucleation, while Na + dopants occupying interstitial sites effectively reduce electron–phonon coupling and alleviate the lattice microstrain. Additional coordination and hydrogen bonding between TANA and the perovskite facilitate the suppression of iodide and lead vacancy defects, reinforcing the driving forces for carrier extraction and transfer. As a result, the optimized device yields a champion power conversion efficiency (PCE) of 26.90% (certified 26.75%), along with excellent long‐term stability, retaining 92.3% of its initial efficiency after 1000 h under continuous operation (ISOS‐L‐2I). Remarkably, a minimodule with an aperture area of 10.24 cm 2 also achieves a remarkable PCE of 23.0%, underscoring the industrial potential of this multifunctional stabilization approach.