Precursor Ink Engineering for Scalable Slot-Die Coating of Perovskite Films for Photovoltaic Mini-Module Production

As the efficiency of small-area perovskite solar cells has reached more than 25% in recent years, it is now essential to accelerate the commercialization of perovskite photovoltaics. Developing low-cost, reliable, and automatic large-area coating techniques is a crucial step toward the industrial production of perovskite solar modules. For large-area solution-based deposition of perovskite films, solvent extraction from the wet precursor film is critical to producing pinhole-free, uniform, and high-quality perovskite films. Here, we report a scalable slot-die coating method for perovskite photovoltaic mini-module production. A vacuum quenching technique is developed to assist the formation of a perovskite intermediate phase by extracting solvents from the precursor films uniformly throughout the coating area. We study the impact of N-Methyl-2-Pyrrolidone (NMP) as a coordinating solvent in the perovskite precursor ink on the quality of slot-die-coated perovskite films and the photovoltaic performance of corresponding devices. We demonstrate small-area cells and 40 cm ² perovskite mini-modules with power conversion efficiencies of up to 19% and 17%, respectively. Furthermore, external radiation efficiency (ERE) measurement carried out to characterize the uniformity of mini-modules and study the perovskite degradation.