Influence of Precursor Density and Conversion Time on the Orientation of Vapor-Deposited ZIF-8

Kräuter, Marianne; Cruz, Alexander John; Stassin, Timothée; Rodríguez‐Hermida, Sabina; Ameloot, Rob; Resel, Roland; Coclite, Anna Maria

doi:10.3390/cryst12020217

Cited by 10 publications

(24 citation statements)

References 41 publications

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“…This phenomenon can be explained by the increased mobility associated with longer linker exposure times (Figure S5). 22,27,52,53 The large-scale spatial uniformity of the ZIF-8 MLD films was verified by coating a 200 mm Si wafer with minimal thickness variation (29.5 ± 2.4 nm), as determined by ex situ ellipsometry mapping, Figure S6.…”

Section: ■ Direct Zif-8 Mldmentioning

confidence: 96%

Molecular Layer Deposition of Zeolitic Imidazolate Framework-8 Films

et al. 2023

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Vapor-phase film deposition of metal–organic frameworks (MOFs) would facilitate the integration of these materials into electronic devices. We studied the vapor-phase layer-by-layer deposition of zeolitic imidazolate framework 8 (ZIF-8) by consecutive, self-saturating reactions of diethyl zinc, water, and 2-methylimidazole on a substrate. Two approaches were compared: (1) Direct ZIF-8 “molecular layer deposition” (MLD), which enables a nanometer-resolution thickness control and employs only self-saturating reactions, resulting in smooth films that are crystalline as-deposited, and (2) two-step ZIF-8 MLD, in which crystallization occurs during a postdeposition treatment with additional linker vapor. The latter approach resulted in a reduced deposition time and an improved MOF quality, i.e., increased crystallinity and probe molecule uptake, although the smoothness and thickness control were partially lost. Both approaches were developed in a modified atomic layer deposition reactor to ensure cleanroom compatibility.

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Section: ■ Direct Zif-8 Mldmentioning

confidence: 96%

Molecular Layer Deposition of Zeolitic Imidazolate Framework-8 Films

et al. 2023

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“…This is in line with previous protocols for the fabrication of thin films bases on different types of MOFs. [49,52]…”

Section: Thin Film Preparationmentioning

confidence: 99%

Identifying the Internal Network Structure of a New Copper Isonicotinate Thin‐Film Polymorph Obtained via Chemical Vapor Deposition

Legenstein

Rodríguez‐Hermida

Rubio‐Giménez

et al. 2023

Adv Materials Inter

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tion of homogeneous films onto solid supports. [9] The presence of a surface during framework formation can strongly influence the crystallization process, even inducing the formation of unknown crystal phases. Such unique polymorphs also appear in thin films of purely organic or inorganic compounds [10] and are commonly referred to as substrate-induced polymorphs or thin-film phases. [11] Detailed knowledge of these crystal structures is essential since thin-film phases can have considerably different properties than bulk polymorphs. [12] MOF thin films and specially surface-coordinated MOFs (SURMOFs) [13,14] are known to feature unprecedented polymorphs [15,16] that are not accessible in bulk form and can strongly impact the performance of MOF-based devices. [17,18] Thin-film phases can occur when the MOF building blocks interact with surface groups, such as selfassembled monolayers, [19,15] or when the substrate is covered with a precursor layer (i.e., a metal oxide or hydroxide). [20,21] In addition, the physical state of the reagents that interact with the solid surface (i.e., in solution or the vapor phase) can be a determining factor. [22][23][24] Unfortunately, standard crystal structure solution methods are unsuitable for unknown MOF thin-film phases. In contrast to single-crystal or powder X-ray diffraction (XRD) methods, [25] the number of diffraction peaks observed in MOF thin films is The preparation of thin films is often associated with the appearance of unknown polymorphs, as both the substrate and deposition method can heavily influence crystallization processes. Here, chemical vapor deposition is used to obtain thin films of a copper-isonicotinate (Cu-INA) metal-organic framework (MOF). Starting from copper-based precursor layers (copper oxide and hydroxide), a solid-vapor conversion with vaporized isonicotinic acid in either a dry or humidified atmosphere, yields a new Cu-INA MOF polymorph. It is found that the crystalline order of the precursor layer has a strong impact on the texture of Cu-INA thin films. Furthermore, a novel methodology is introduced to determine the structure of a previously unknown thin-film phase of Cu-INA. Although only a few diffraction peaks are found via synchrotron grazing incidence X-ray diffraction (GIXRD), a triclinic unit cell can be determined, and Patterson functions can be calculated. The latter reveals the position of the copper atoms within the unit cell and the alignment of the INA linkers defining the coordination network structure. This work introduces how the combination of GIXRD data with Patterson functions can be used to identify the structure of an unknown thin-film MOF polymorph.

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“…1c), in line with roughness observed in the literature for samples with comparable thickness. 18,35,36 The ZIF-8 formation is further confirmed by in-plane XRD analysis, infrared spectroscopy, XPS and TOF-SIMS. The diffraction peaks observed in the XRD analysis of the as-deposited sample after 10 exposures, ZIF-8@10_exposures , correspond to ZIF-8 sodalite type structure (Fig.…”

Section: Resultsmentioning

confidence: 75%