Colloidal Ink Engineering for Slot‐Die Processes to Realize Highly Efficient and Robust Perovskite Solar Modules

Perovskite solar cells (PSCs) have emerged as a promising alternative to silicon solar cells, but challenges remain in developing perovskite inks and processes suitable for large-scale production. This study introduces a novel approach using colloidal inks incorporating toluene and chlorobenzene as co-antisolvents for PSC fabrication via slot-die process. It is found that colloidal inks that are strategically engineered can significantly improve the rheological properties of perovskite inks, leading to enhanced wettability and high-quality film formation. The formation of large colloids such as α cubic perovskite, δ hexagonal perovskite and transition intermediate phases promotes heterogeneous nucleation and lowers activation energy for crystallization, resulting in superior crystal growth and improved film morphology. Notably, the co-solvent enhances the FA-PbI₃ binding energy and weakens the dimethyl sulfoxide coordination, which is more thermodynamically favorable for perovskite crystallization. This colloidal strategy yields devices with a maximum efficiency of 21.32% and remarkable long-term stability, retaining 77% of initial efficiency over 10115 h. The study demonstrates the scalability of this approach, achieving 20.26% efficiency in lab-scale minimodules and 19.15% in larger convergence minimodules. These findings provide an understanding of the complex relationship between ink composition, rheological properties, film quality, crystallization kinetics, and device performance.