Integrating metal-organic frameworks (MOFs) in microelectronics has disruptive potential because of the unique properties of these microporous crystalline materials. Suitable film deposition methods ...are crucial to leverage MOFs in this field. Conventional solvent-based procedures, typically adapted from powder preparation routes, are incompatible with nanofabrication because of corrosion and contamination risks. We demonstrate a chemical vapour deposition process (MOF-CVD) that enables high-quality films of ZIF-8, a prototypical MOF material, with a uniform and controlled thickness, even on high-aspect-ratio features. Furthermore, we demonstrate how MOF-CVD enables previously inaccessible routes such as lift-off patterning and depositing MOF films on fragile features. The compatibility of MOF-CVD with existing infrastructure, both in research and production facilities, will greatly facilitate MOF integration in microelectronics. MOF-CVD is the first vapour-phase deposition method for any type of microporous crystalline network solid and marks a milestone in processing such materials.
The invention of the scanning tunneling microscope has led to the visualization of molecules in real space on atomically flat conductive substrates. This has boosted research into supramolecular ...chemistry on surfaces. In this Review, we highlight recent developments in the design and functionality of supramolecular surface patterns, with special attention paid to those networks which are chiral or contain a high degree of porosity as well as to the reactivity, which is one of the most important recent developments in supramolecular surface chemistry.
The properties of graphene nanoribbons (GNRs) make them good candidates for next-generation electronic materials. Whereas 'top-down' methods, such as the lithographical patterning of graphene and the ...unzipping of carbon nanotubes, give mixtures of different GNRs, structurally well-defined GNRs can be made using a 'bottom-up' organic synthesis approach through solution-mediated or surface-assisted cyclodehydrogenation reactions. Specifically, non-planar polyphenylene precursors were first 'built up' from small molecules, and then 'graphitized' and 'planarized' to yield GNRs. However, fabrication of processable and longitudinally well-extended GNRs has remained a major challenge. Here we report a bottom-up solution synthesis of long (>200 nm) liquid-phase-processable GNRs with a well-defined structure and a large optical bandgap of 1.88 eV. Self-assembled monolayers of GNRs can be observed by scanning probe microscopy, and non-contact time-resolved terahertz conductivity measurements reveal excellent charge-carrier mobility within individual GNRs. Such structurally well-defined GNRs may prove useful for fundamental studies of graphene nanostructures, as well as the development of GNR-based nanoelectronics.
Halogen bonds, which provide an intermolecular interaction with moderate strength and high directionality, have emerged as a promising tool in the repertoire of non‐covalent interactions. In this ...review, we provide a survey of the literature where halogen bonding was used for the fabrication of supramolecular networks on solid surfaces. The definitions of, and the distinction between halogen bonding and halogen‐halogen interactions are provided. Self‐assembled networks formed at the solution/solid interface and at the vacuum‐solid interface, stabilized in part by halogen bonding, are discussed. Besides the broad classification based on the interface at which the systems are studied, the systems are categorized further as those sustained by halogen‐halogen and halogen‐heteroatom contacts.
A survey of systems in which halogen bonding was used for the fabrication of supramolecular networks on solid surfaces is reported. Self‐assembled networks formed at the solution/solid interface and at the vacuum/solid interface, stabilized in part by halogen bonding, are discussed.
Scanning tunnelling microscope observations at the 1‐phenyloctane/graphite interface reveal how chiral structural information at the molecular level is transferred and expressed structurally at the ...2D supramolecular level for a porous system. The chirality of self‐assembled molecular networks formed by chiral dehydrobenzo12annulene (cDBA) derivatives having three chiral chains and three achiral chains, alternatingly, is compared with those of cDBAs having six chiral chains reported previously. While for all cDBAs homochiral surfaces are formed, their handedness is not simply a reflection of the absolute configuration of the stereogenic centres. Both the number of stereogenic centres as well as the length of the achiral chains determine the supramolecular handedness, providing a deep insight into the supramolecular chirality induction mechanisms at play. Moreover, these cDBAs act to induce chirality in porous networks formed by achiral DBAs.
Right or left? The centers decide: STM observations at the liquid/graphite interface reveal chirality of self‐assembled porous molecular networks formed by chiral molecules having three chiral and three achiral chains. While homochiral surfaces are formed for all chiral molecules, the number of stereogenic centres and the length of the achiral chains determine the supramolecular handedness.
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