Scalable Two‐Step Production of High‐Efficiency Perovskite Solar Cells and Modules

Perovskite solar cells (PSCs) fabricated in laboratories have already achieved a power conversion efficiency (PCE) comparable to market‐dominant crystalline silicon solar cells. However, this promising photovoltaic technology suffers from severe loss of PCE during scaling up, limiting its progress toward commercialization. One critical question is to develop scalable, low‐cost, high throughput, and well‐controlled production methods to deposit high‐quality perovskite films. Among various approaches, two‐step sequential deposition methods have their unique advantages but have been long overlooked. This review provides an overview of two‐step methods for fabricating efficient and stable perovskite solar modules (PSMs). The mechanisms of two‐step perovskite conversion and advanced engineering approaches to modulate the perovskite formation process are discussed first. The progress of efficient PSCs prepared by different two‐step methods is surveyed and the advantages and disadvantages of each method for the scalable production of PSMs are compared. Particularly, it is highlighted that the vapor‐based two‐step methods are promising for high‐throughput in‐line production of PSMs. Finally, insights into the challenges and outlook of the industrialization of two‐step processes for producing PSMs are provided.