Blade Coating Inverted Perovskite Solar Cells with Vacuum‐Assisted Nucleation Based on Bottom Quasi‐2D Passivation

Metal halide perovskite solar cells (PSCs) attract an enormous attention because of their high power conversion efficiency (PCE) and low fabrication cost. However, their commercialization is limited by fabricating highly efficient large‐area solar cells. Controlling the morphology and crystallization of perovskite for large‐area fabrication is difficult but important. Herein, a vacuum‐assisted approach is developed to obtain mirror‐like, pinhole‐free, highly crystalline, and uniform blade‐coated perovskite films, without the use of antisolvent and air knife. This method can be a universal approach for various perovskite compositions. Meanwhile, the phenethylammonium iodide passivation effect at the top and bottom interfaces of perovskite layer based on FTO/NiOx/perovskite/C60/BCP/Cu inverted p‐i‐n structure is systematically investigated. The optimized device fabricated by blade coating under an ambient environment exhibits the champion PCE of 20.7% and is among the top few records of blade coating inverted structure based on NiOx hole transport layer. The encapsulated device retains 97% of its maximum efficiency under open‐circuit condition after 1000 h of photostability test in an ambient environment at room temperature with a relative humidity of 40–60%. Herein, low‐cost, easy, and reproducible strategies to fabricate efficient and stable blade‐coated PSCs are demonstrated. This article reveals that quasi‐2D bottom passivation improves inverted perovskite solar cell device performance. The vacuum‐assisted blade coating perovskite solar cells fabricated in the ambient environment using NiOx as hole transport layer achieve an efficiency of 20.7%, paving the way for developing highly efficient, large‐area, low‐cost, and stable perovskite solar cells.