The Effect of Interfacial Humidity on the Printing of Highly Reproducible Perovskite Solar Cells in the Air

Abstract Moisture is a double‐edged sword in the nucleation and crystallization of perovskite films. In the presence of appropriate moisture in the air, grain boundaries are expected to merge neighboring grains, promoting the conversion of unreacted ions, resulting in large grains and pinhole‐free films. Adversely, excessive moisture can have detrimental effects on perovskite by damaging its crystalline structure. Controlling humidity precisely and removing excessive moisture from the interface is crucial to the printing of high‐quality and reproducible films in the air, which will undoubtedly promote the rapid commercialization of perovskite solar cells. Here, a method for high‐yield printing of perovskite films is developed using interfacial moisture as a research object. The finite element simulation reveals that interfacial moisture is the key factor affecting the quality of perovskite film formation, regardless of the ambient moisture. The results show that when the interfacial humidity is in the range of 7%–25%, the films exhibit high‐quality crystallization. The devices produced by this method exhibit a yield of 92%, indicating a promising pathway to attain highly reproducible perovskite films with superior optoelectronic properties. The air‐printing process will provide a broad guide to the commercial manufacture of high‐performance perovskite optoelectronic devices.