Vapor-phase methods for synthesizing metal-organic framework thin films

Due to their unique structures and exceptional physical and chemical properties, metal-organic framework (MOF) materials have garnered extensive attention in various fields, including catalysis, separations, sensing, and optics. Compared with powders or bulk MOF materials, MOF thin films exhibit large vertical and horizontal dimensions, higher specific surface areas, and abundant active sites and undergo facile combination with other functional centers for adsorption/separation, catalysis, and photoelectronic device applications. Among the methods used in preparing MOF thin films, the vapor phase approach enables more effective growth of MOF films with controllable thicknesses, uniformity, and compatibility; thus, it has attracted significant interest. This extensive review presents four vapor-phase approaches for preparing MOF thin films: the steam-assisted conversion method, vapor-phase transformations of metal oxide templates, vapor-phase linker exchange, and the atomic layer deposition/molecular layer deposition method. We summarize the advantages and disadvantages of these different vapor-phase-based methods for thin-film preparation, aiming to promote their use in precise and controllable surface syntheses.