Chloride Additive Optimization in Ultrasonic Spray Coating Process for High‐Performance Perovskite Solar Cell Realization

ABSTRACT Perovskite solar cells (PSCs) have depicted potential for practical applications mainly because of their high efficiency and low cost. Thereby, large‐scale perovskite solar module production becomes essential for its industrialization. The ultrasonic spray coating process, with its straightforward operation and ability to produce high‐quality film, holds great commercialization promise. Despite this, there is limited research on precursor solution engineering for spray coating, and as a result, the performance of PSCs fabricated utilizing spray coating still has room for improvement compared with traditional spin coating methods. In this work, we explored and optimized perovskite precursor solutions in the spray coating process by introducing chloride additives. Meanwhile, the corresponding mechanism is systematically investigated. Accordingly, we successfully fabricated PSCs with efficiencies of 22.34% for small‐area devices and 18.90% for large‐area ones through the ultrasonic spray coating process. This represents one of the highest PCEs reported to date for PSCs fabricated via spray coating.