Roll‐to‐Roll Processes for the Fabrication of Perovskite Solar Cells under Ambient Conditions

Recent progress in the engineering and fabrication optimization of hybrid perovskite solar cells (PSCs) has led to power conversion efficiencies (PCEs) of up to 25.2%. The properties of perovskite solutions enable low‐temperature, scalable coating methods that are compatible with the roll‐to‐roll (R2R) fabrication process. Despite this, there is still a significant lag in efficiency in large‐area devices fabricated using the R2R process, which achieves PCEs of 50% of the record value. Direct translation of research results to large‐scale commercially acceptable levels is crucial for commercialization, along with long‐term durability and processing reproducibility of the different device layers. Herein, the recent progress of several coating and R2R processes for the formation of PSC layers, detailing the key variables involved in the process, with an emphasis on the nucleation and crystallization of the perovskite film, is considered. The barriers and challenges in producing high‐quality perovskite films and improving the stability of devices are discussed. In addition, stability protocols for PSCs are discussed as they are key to unifying PSC stability and performance assessment, which is required to gain a better understanding of the different compounds and layers used in cell fabrication and the approaches necessary for their optimization.