Dynamic Reconstruction of Fluid Interface Manipulated by Fluid Balancing Agent for Scalable Efficient Perovskite Solar Cells

Abstract Laboratory‐scale spin‐coating techniques are widely employed for fabricating small‐size, high‐efficiency perovskite solar cells. However, achieving large‐area, high‐uniformity perovskite films and thus high‐efficiency solar cell devices remain challenging due to the complex fluid dynamics and drying behaviors of perovskite precursor solutions during large‐area fabrication processes. In this work, a high‐quality, pinhole‐free, large‐area FAPbI ₃ perovskite film is successfully obtained via scalable blade‐coating technology, assisted by a novel bidirectional Marangoni convection strategy. By incorporating methanol (MeOH) as a fluid balance agent, the direction of Marangoni convection is effectively regulated, mitigating the disordered motion of colloidal precursor particles during the printing process. As a result, champion power conversion efficiencies (PCEs) of 24.45% and 20.32% are achieved for small‐area FAPbI ₃ devices (0.07 cm ² ) and large‐area modules (21 cm ² ), respectively. Notably, under steady illumination, the device reached a stabilized PCE of 24.28%. Furthermore, the unencapsulated device exhibited remarkable operational stability, retaining 92.03% of its initial PCE after 1800 h under ambient conditions (35 ± 5% relative humidity, 30 °C). To demonstrate the universality of this strategy, a blue perovskite light‐emitting diode is fabricated, showing an external quantum efficiency (EQE) of 14.78% and an electroluminescence wavelength (EL) of 494 nm. This work provides a significant technique for advancing solution‐processed, industrial‐scale production of high‐quality and stable perovskite films and solar cells.