Benchmarking Inorganic Deposition Routes for Hybrid Two‐Step Processed Perovskite Solar Cells: A Materials Perspective

As the perovskite solar cell (PSC) industry moves toward large‐scale manufacturing, production processes must enable high‐throughput fabrication and simple process integration. The hybrid two‐step deposition route has emerged as a promising method for achieving conformal coatings on micron‐scale textures, a critical feature for perovskite/silicon tandem photovoltaics. In this work, we present a fully sequential route, wherein the inorganic materials CsCl and PbI2 are deposited separately, allowing for facile industrial implementation as compared to the commonly codeposited inorganic scaffold. Microstructural analysis reveals a change in preferred crystal orientation of the PbI2 platelets with codeposition resulting in horizontal growth, whereas sequential deposition promotes vertical growth with a secondary tilted orientation. Elemental mapping of the final perovskite absorber shows homogeneous distribution of Cs, formamidinium, and I, while Pb and Cl largely retain their initial scaffold positions. PSCs fabricated via sequential deposition of the inorganic scaffold demonstrate improved process repeatability and reach an efficiency of 20.3%, ranking among the highest reported efficiencies for wide‐bandgap hybrid two‐step processed PSCs. ... mehrThese findings underscore the potential of fully sequential hybrid deposition as a viable route toward industrial PSC production.