Scalable Slot‐Die Coating of Passivation Layers for Improved Performance of Perovskite Solar Cell Modules

Upscaling the perovskite solar cell (PSC) while avoiding losses in the power conversion efficiency presents a substantial challenge, especially when transitioning from ≤1 cm² cells to ≥10 cm² modules. In addition to the fabrication of key functional layers, scalable technologies for surface passivation, considered indispensable for achieving high-performance PSCs, are urgently required. However, studies on this topic remain limited. In this study, an industry-ready slot-die coating method for the effective passivation of perovskite films as a practical alternative is developed to the spin-coating procedures commonly used in research. The coating conditions and molecular structure of the passivation agent are systematically optimized to achieve high-quality film morphology and substantially suppress interface recombination. 2-chloro-5-(trifluoromethyl)-phenylammonium bromide exhibited the best results, improving the open-circuit voltage of cells and subcells in a module by 80 ± 4 and 72 ± 10 mV, respectively. Correspondingly, the larger-area (active area: 10 cm²) modules sustained the highest efficiency of 21.9% under simulated 1-sun irradiation. The encapsulated devices retained 94% of their initial performances after 750 h of continuous operation. The proposed surface-passivation slot-die technology is compatible with high-throughput processes and is employable for large-scale PSC fabrication.