Closed-Loop Slit-Flushing Antisolvent Strategy Enables Controlled Three-Dimensional Mass Transfer for Large-Area Perovskite Solar Cells.

The antisolvent process remains the dominant fabrication route for high-efficiency perovskite solar cells (PSCs), but its scalability is constrained by intrinsic mass transfer characteristics and the requirements of green manufacturing. To address these challenges, we develop a closed-loop slit-flushing antisolvent (SFA) strategy that offers ambient-air processability, antisolvent recyclability, and a three-dimensional controllable mass transfer regime. By creating a pressure-driven forced flow within a parallel-plate slit, we transform the mass transfer mechanism from a purely vertical diffusion-dominated regime of static bathing to a synergistic combination of horizontal forced convection and vertical diffusion, which ensures uniform and controllable nucleation over large-area films. With an optimized slit height of 0.5 mm, the SFA method yields highly uniform, compact, and pinhole-free perovskite films in ambient air on a 100 × 100 mm substrate, with reduced defect density and a homogenized distribution. Small-area PSCs achieve a champion power conversion efficiency (PCE) of 24.59%, while the champion large-area flexible module with an aperture area of 61.2 cm2 delivers a laboratory PCE of 18.69% and a certified PCE of 17.35%. This study presents a straightforward, low-cost, and practical solution to the scaling bottleneck of antisolvent methods, enabling the fabrication of efficient and stable large-area perovskite photovoltaics.