Scalable Preparation of High‐Performance ZnO–SnO₂ Cascaded Electron Transport Layer for Efficient Perovskite Solar Modules

Perovskite solar cells are the fastest‐growing photovoltaic technology in recent years. However, together with the stability, the low‐cost and high‐quality preparation of large‐area modules still limits their commercialization process. Herein, a scalable and high‐performance ZnOSnO₂ cascade double‐layer electron transport layer (ETL) for efficient and stable perovskite modules is reported. The cascaded ETL is fabricated using a simple spray pyrolysis coating combined with the blade coating process, which not only effectively improves the interface stability by avoiding the protonation of ZnO to maintain its high electron mobility, but also provides a much smoother surface for the crystallization of perovskites. In addition, the well‐matched conduction band level between SnO₂ and perovskites ensures the improvement of open‐circuit voltage. Subsequently, combined with the blade‐coated perovskite layer and hole transport layer film, large‐area planar perovskite modules are successfully prepared. These high‐quality films enable the perovskite solar modules to achieve impressive efficiencies of 17.8% in the module size 6 × 6 cm² and 16.6% in a size of 10 × 10 cm². The obtained module also shows excellent reproducibility and stability. The high‐performance ETL and the related deposition method developed in this work are promising for applications in the industrial scalable perovskite modules’ fabrication.