Search

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. [ABSTRACT FROM AUTHOR]

The multiple quantum wells (QWs) distribution in low‐dimensional perovskite films hinders charge transport due to the fundamental difficulty of controlling crystal growth from precursor solutions, yielding poorly homogeneous low‐dimensional perovskite solar cells (PSCs), especially in upscaling fabrication. Here, efficient low‐dimensional PSCs are realized by modulating the colloidal assembly behavior in the precursor solution to induce intermediate structures. In combination with in situ liquid time‐of‐flight secondary ion mass spectrometry, the assembly behavior of organic cations involved lead iodide‐dominated colloidal soft framework is visualized by investigating the precursor species differences under hydrogen bonding interactions. Subsequently, solid‐state reactions emerge and the formamidine (FA)‐based perovskite films exhibit significantly suppressed multiple QWs distribution. Encouragingly, the FA device (n=9, by meniscus‐assisted coating) achieves a power conversion efficiency (PCE) of 20.28 % for a size of 0.04 cm2 and a PCE of 15.35 % for a mini‐module of 16.94 cm2 with superior stability. [ABSTRACT FROM AUTHOR]

Homogeneity and stability of flexible perovskite solar cells (PSCs) are significant for the commercial feasibility in upscaling fabrication. Concretely, the mismatching between bottom interface and perovskite precursor ink can cause uncontrollable crystallization and undesired dangling bonds during the printing process. Herein, methylammonium acetate, serving as ink assistant (IAS) can effectively avoid the micron‐scale defects of perovskite film. The in situ optical microscope is applied to prove the IAS can inhibit the colloidal aggregation and induce more adequate crystallization growth, thus avoiding the micron‐scale defects of pinholes and intergranular cracking. Concurrently, 4‐chlorobenzenesulfonic acid is introduced into the electrode surface as a passivation layer to restore the deep traps at perovskite interface in nano‐scale. Finally, the target flexible devices (1.01 cm2) deliver a superior efficiency of 18.12% with improved air atmosphere stability. This multi‐scale defect repair strategy provides an integrated design concept of homogeneity and stability for scalable and flexible PSCs. [ABSTRACT FROM AUTHOR]