Progress in scalable coating and roll-to-roll compatible printing processes of perovskite solar cells toward realization of commercialization

Organic–inorganic halide perovskite solar cells (PeSCs) have attracted worldwide attention due to their excellent photovoltaic properties, such as their proper bandgap, strong light absorption, long exciton diffusion length, and easy device fabrication with solution processes, suggesting a great potential for low-cost, high-performance solar cells. After a power conversion efficiency (PCE) of 3.8% achieved in 2009, numerous efforts have been made to create PeSCs with high PCEs over 20% in small-area cells. The next challenge is transition from the lab-scale spin coating to a large-scale coating/printing, which will preferably involve the cost-competitive roll-to-roll manufacturing and vacuum-free full-printing process. This review provides a progress report on studies related to the scalable deposition methods for PeSCs, such as slot-die coating, blade coating, spray coating, and various other methods, and to their processing strategies for morphology control in perovskite film formation and discusses the challenges and potential of commercialization of PeSCs in the future.