Understanding crystallization processes and their pathways in metal‐halide perovskites is of crucial importance as this strongly affects the film microstructure, its stability, and device performance. While many approaches are developed to control perovskite formation, the mechanisms of film formation are still poorly known. Using time‐resolved in situ grazing incidence wide‐angle X‐ray scattering, the film formation of perovskites is investigated with average stoichiometry Cs_0.15FA_0.85PbI₃, where FA is formamidinium, using the popular antisolvent dropping and gas jet treatments and this is contrasted with untreated films. i) The crystallization pathways during spin coating, ii) the subsequent postdeposition thermal annealing, and iii) crystallization during blade coating are studied. The findings reveal that the formation of a nonperovskite FAPbI₃ phase during spin coating is initially dominant regardless of the processing and that the processing treatment (e.g., antisolvent dropping, gas jet) has a significant impact on the as‐cast film structure and affects the phase evolution during subsequent thermal treatment. It is shown that blade coating can be used to overcome the nonperovskite phase formation via solvothermal direct crystallization of perovskite phase. This work shows how real‐time investigation of perovskite formation can help to establish processing–microstructure–functionality relationships.

中文翻译：

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加工对成膜过程中混合金属卤化物钙钛矿结构和组成演变的影响

了解结晶过程及其在金属卤化物钙钛矿中的途径至关重要，因为这会严重影响膜的微观结构，稳定性和器件性能。尽管开发了许多方法来控制钙钛矿的形成，但是膜形成的机理仍知之甚少。利用时间分辨的原位掠射入射广角X射线散射，以平均化学计量Cs _0.15 FA _0.85 PbI ₃研究钙钛矿的膜形成。，其中FA是甲ami，使用流行的抗溶剂滴落和气体喷射处理，这与未经处理的薄膜形成对比。i）研究了旋涂过程中的结晶途径，ii）随后的沉积后热退火，以及iii）刮涂过程中的结晶过程。研究结果表明，非钙钛矿型FAPbI ₃的形成不管处理如何，旋涂过程中的相最初都是占主导地位的，并且处理处理（例如，抗溶剂滴落，气体喷射）对铸膜结构具有重大影响，并影响后续热处理期间的相演变。结果表明，叶片涂层可用于通过钙钛矿相的溶剂热直接结晶来克服非钙钛矿相的形成。这项工作表明钙钛矿形成的实时调查如何帮助建立加工-微观结构-功能关系。