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

Abstract 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‐PbI 3 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.