Scalable Production of High Performance Flexible Perovskite Solar Cells via Film-Growth-Megasonic-Spray-Coating System

Commercialization of flexible perovskite solar cells requires an effective scalable coating system that overcomes the inadequate wettability of conventional polymer-based flexible substrates. In this study, we have come up with a Film-Growth-Megasonic-Spray-Coating (FGMSC) method that continuously grows uniform perovskite film on large-area flexible substrates by using fine perovskite precursor droplets (< 10 mu m). The film growth mechanisms of a perovskite layer (e.g. film coverage, roughness, and crystal grain size) according to the precursor droplet supply rate and the multiple spray was thoroughly investigated for manufacturing flexible perovskite solar mini-module. In complete automation that utilizes the two-dimensional transportation system, the FGMSC system has successfully fabricated a defect-free uniform perovskite layer on large-area flexible substrates with high reproducibility and flexibility by controlling perovskite film growth. The scalability of this system is proved through fabrication of a flexible perovskite solar mini-module with PCE of 16.10% from an active area of 35.1 cm(2), which is the highest efficiency made by continuous spray coating systems. The encapsulated flexible mini-module retained 97% of its initial efficiency after 200 h under continuous 1-sun illumination. The results have suggested that f-PSCs can be effectively commercialized by using our FGMSC system.