Out-of-equilibrium processes in crystallization of organic-inorganic perovskites during spin coating.
Nat Commun 2021;
12:5624. [PMID:
34561460 PMCID:
PMC8463609 DOI:
10.1038/s41467-021-25898-5]
[Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 06/08/2021] [Indexed: 12/04/2022] Open
Abstract
Complex phenomena are prevalent during the formation of materials, which affect their processing-structure-function relationships. Thin films of methylammonium lead iodide (CH3NH3PbI3, MAPI) are processed by spin coating, antisolvent drop, and annealing of colloidal precursors. The structure and properties of transient and stable phases formed during the process are reported, and the mechanistic insights of the underlying transitions are revealed by combining in situ data from grazing-incidence wide-angle X-ray scattering and photoluminescence spectroscopy. Here, we report the detailed insights on the embryonic stages of organic-inorganic perovskite formation. The physicochemical evolution during the conversion proceeds in four steps: i) An instant nucleation of polydisperse MAPI nanocrystals on antisolvent drop, ii) the instantaneous partial conversion of metastable nanocrystals into orthorhombic solvent-complex by cluster coalescence, iii) the thermal decomposition (dissolution) of the stable solvent-complex into plumboiodide fragments upon evaporation of solvent from the complex and iv) the formation (recrystallization) of cubic MAPI crystals in thin film.
Complex phenomena are prevalent during the formation of materials, and they affect the processing structure-function relationship. Here the authors elucidate the stochastic transformation processes happening during the spin coating of perovskite colloidal precursors by multimodal characterization.
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