Slot‐Die Coating for Scalable Fabrication of Perovskite Solar Cells and Modules

Abstract Solution‐coating processes are promising methods to form active layers with low‐cost input in the industrial development of perovskite solar devices. Among available coating processes, of particular interest are those capable of producing uniform coatings with small defect distribution over large areas at high speeds, referred to as scalable methods. Slot‐die coating is one of these methods. It involves the meniscus coating of liquids or solutions over a static or moving substrate. This review discusses recent advances in slot‐die coating of active layers used in perovskite solar cells (PSCs) and modules (PSMs). Various strategies to control ink spreading over substrates, wet film drying, and post‐coating crystallization of light‐absorbing perovskite layer are outlined along with different approaches and materials used in post‐deposition defects healing. Then, commonly used solvents for perovskite ink formulation are analyzed based on their specific rheology and potential effect on human health and equipment safety. Also, precursor materials, solvents, and strategies to obtain desirable properties and morphology in the slot‐die coating of charge‐transporting layers are discussed. Lastly, an analysis of the performance of slot‐die coated perovskite solar mini‐modules and future perspectives on this topic conclude this review.