Ultrafast Growth of High-Quality Cs_0.14FA_0.86Pb(Br_xI_1–x)₃ Thin Films Achieved Using Super-Close-Space Sublimation

Solar cells employed by organic–inorganic hybrid perovskite light absorbers have become a hot research subject for both the scientific community and industrial community in the past several years. Due to the low cost and easy synthesis, they are one of the most commercially valuable photovoltaic materials. At present, spin-coating is still employed as the conventional technology for the deposition of the perovskite thin films owing to its simple manipulation in the lab. However, in the photovoltaic industry, spin-coating is not an option for the manufacturing scaling toward a gigawatt-scale capacity. In this work, we demonstrated an improved close-space sublimation method with a very close distance (∼200 μm) between the vapor source and the substrate. By using this method, we can transform the thermally deposited large-area CsI/PbI2 layer (20 × 20 cm2) into a CsFA-based perovskite film in just a few minutes. The perovskite solar cells with Cs0.14FA0.86Pb(BrxI1–x)3 thin films fabricated using the FAI/FABr mixed-vapor reaction showed an outstanding power conversion efficiency of up to 20.45%. The champion 5 × 5 cm2 mini-modules exhibited a high efficiency of up to 17.0%, manifesting the good upscaling ability of the super-close-space sublimation technique.