Large-area high-efficiency perovskite solar cells based on perovskite films dried by the multi-flow air knife method in air

Perovskite solar cells are extremely promising high-efficiency low-cost photovoltaic devices. However, large-area and uniform perovskite film fabrication in air is still a big challenge for the mass production of highly efficient perovskite solar cells. Here, we first report the novel multi-flow air knife (MAK) method to control the formation of large-area perovskite films in ambient air. The proposed MAK method, based on the comprehensive understanding of the solution film evaporation process, entails the use of multiple gas flows that rapidly dry the solution and enable the production of large-area perovskite films in air. By adopting the MAK technology, high-quality films with full surface coverage and a low surface roughness of 4.98 nm over a 10 × 10 μm² scan area were successfully fabricated. Highly reproducible power conversion efficiencies up to 11.70% were achieved with an active area of 1.0 cm². The highest efficiency of 17.71%, obtained for a device with an area of 0.1 cm², further demonstrated the promising potential of this technology. Thus, the MAK technology enables the low-cost fabrication of highly efficient perovskite solar cells, paving the way for the mass production of low-cost high-performance perovskite solar cells in ambient air.