Hybrid Perovskite Thin‐Film Photovoltaics: In Situ Diagnostics and Importance of the Precursor Solvate Phases

Solution‐processed hybrid perovskite semiconductors attract a great deal of attention, but little is known about their formation process. The one‐step spin‐coating process of perovskites is investigated in situ, revealing that thin‐film formation is mediated by solid‐state precursor solvates and their nature. The stability of these intermediate phases directly impacts the quality and reproducibility of thermally converted perovskite films and their photovoltaic performance.