Scalable Fabrication of High‐Performance Perovskite Solar Cell Modules by Mediated Vapor Deposition

Abstract Perovskite solar cells (PSCs) can enable renewable electricity generation at low levelized costs, subject to the invention of an economically feasible technology for their large‐scale fabrication, like vapor deposition. This approach is effective for the fabrication of small area (<1 cm 2 ) PSCs, but its scale‐up to produce high‐efficiency larger area modules has been limited by a severe imbalance between the vapor‐solid reaction kinetics and the mass‐transport of the volatile ammonium salt precursor. In this study, an amidine‐based low‐dimensional perovskite is introduced as an intermediate of the solid‐vapor reaction to help resolve this limitation. This improves reaction pathway produces unique vertically monolithic grains with no detectable horizontal boundaries, which is used to produce 1.0 cm 2 PSCs with an efficiency of 22.1%, as well as 12.5 and 48 cm 2 modules delivering 21.1% and 20.1% efficiency, respectively. The modules retain ≈85% of their initial performance after 900 h of continuous operation (ISOS‐L‐1 protocol) and ≈100% after 2800 h of storage in an ambient environment (ISOS‐D‐1 protocol).