ORCID Profile
0000-0003-3246-4072
Current Organisations
Ulsan National Institute of Science and Technology
,
Institute for Basic Science
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Publisher: American Chemical Society (ACS)
Date: 20-02-2017
DOI: 10.1021/ACS.NANOLETT.6B04459
Abstract: Folded graphene in which two layers are stacked with a twist angle between them has been predicted to exhibit unique electronic, thermal, and magnetic properties. We report the folding of a single crystal monolayer graphene film grown on a Cu(111) substrate by using a tailored substrate having a hydrophobic region and a hydrophilic region. Controlled film delamination from the hydrophilic region was used to prepare macroscopic folded graphene with good uniformity on the millimeter scale. This process was used to create many folded sheets each with a defined twist angle between the two sheets. By identifying the original lattice orientation of the monolayer graphene on Cu foil, or establishing the relation between the fold angle and twist angle, this folding technique allows for the preparation of twisted bilayer graphene films with defined stacking orientations and may also be extended to create folded structures of other two-dimensional nanomaterials.
Publisher: Elsevier BV
Date: 06-2018
Publisher: American Chemical Society (ACS)
Date: 02-11-2016
DOI: 10.1021/JACS.6B08625
Abstract: Few-layer graphenes, supported on Si with a superficial oxide layer, were subjected to a Birch-type reduction using Li and H
Publisher: American Chemical Society (ACS)
Date: 09-08-2017
Abstract: Rational bottom-up construction of two-dimensional (2D) covalent or noncovalent organic materials with precise structural control at the atomic or molecular level remains a challenge. The design and synthesis of metal-organic frameworks (MOFs) based on new building blocks is of great significance in achieving new types of 2D monolayer MOF films. Here, we demonstrate that a complexation between copper(II) ions and tri(β-diketone) ligands yields a novel 2D MOF structure, either in the form of a powder or as a monolayer film. It has been characterized by Fourier transform infrared, Raman, ultraviolet-visible, X-ray photoelectron, and electron paramagnetic resonance spectroscopies. Selected area electron diffraction and powder X-ray diffraction results show that the MOF is crystalline and has a hexagonal structure. A MOF-based membrane has been prepared by vacuum filtration of an aqueous dispersion of the MOF powder onto a porous Anodisc filter having pore size 0.02 μm. The porous MOF membrane filters gold nanoparticles with a cutoff of ∼2.4 nm.
Publisher: Springer Science and Business Media LLC
Date: 20-01-2020
DOI: 10.1038/S41565-019-0622-8
Abstract: High-quality AB-stacked bilayer or multilayer graphene larger than a centimetre has not been reported. Here, we report the fabrication and use of single-crystal Cu/Ni(111) alloy foils with controllable concentrations of Ni for the growth of large-area, high-quality AB-stacked bilayer and ABA-stacked trilayer graphene films by chemical vapour deposition. The stacking order, coverage and uniformity of the graphene films were evaluated by Raman spectroscopy and transmission electron microscopy including selected area electron diffraction and atomic resolution imaging. Electrical transport (carrier mobility and band-gap tunability) and thermal conductivity (the bilayer graphene has a thermal conductivity value of about 2,300 W m
Publisher: American Chemical Society (ACS)
Date: 12-05-2017
Publisher: Wiley
Date: 03-06-2019
Abstract: A macroscopic film (2.5 cm × 2.5 cm) made by layer-by-layer assembly of 100 single-layer polycrystalline graphene films is reported. The graphene layers are transferred and stacked one by one using a wet process that leads to layer defects and interstitial contamination. Heat-treatment of the s le up to 2800 °C results in the removal of interstitial contaminants and the healing of graphene layer defects. The resulting stacked graphene s le is a freestanding film with near-perfect in-plane crystallinity but a mixed stacking order through the thickness, which separates it from all existing carbon materials. Macroscale tensile tests yields maximum values of 62 GPa for the Young's modulus and 0.70 GPa for the fracture strength, significantly higher than has been reported for any other macroscale carbon films microscale tensile tests yield maximum values of 290 GPa for the Young's modulus and 5.8 GPa for the fracture strength. The measured in-plane thermal conductivity is exceptionally high, 2292 ± 159 W m
Location: United States of America
Location: Korea, Republic of
No related grants have been discovered for Zonghoon Lee.