Synchrotron Radiation‐Based In Situ GIWAXS for Metal Halide Perovskite Solution Spin‐Coating Fabrication

Abstract Solution‐processable perovskite‐based devices are potentially very interesting because of their relatively cheap fabrication cost but outstanding optoelectronic performance. However, the solution spin‐coating process involves complicated processes, including perovskite solution droplets, nucleation of perovskite, and formation of intermediate perovskite films, resulting in complicated crystallization pathways for perovskite films under annealing. Understanding and therefore controlling the fabrication process of perovskites is difficult. Recently, synchrotron radiation‐based in situ grazing‐incidence wide‐angle X‐ray scattering (GIWAXS) techniques, which possess the advantages of high collimation, high resolution, and high brightness, have enabled to bridge complicated perovskite structure information with device performance by revealing the real‐time crystallization pathways of perovskites during the spin‐coating process. Herein, the developments of synchrotron radiation‐based in situ GIWAXS are discussed in the study of the crystallization process of perovskites, especially revealing the important crystallization mechanisms of state‐of‐the‐art perovskite optoelectronic devices with high performance. At the end, several potential applications and challenges associated with in situ GIWAXS techniques for perovskite‐based devices are highlighted.