Hee Cheul Choi

Nanotube/nanoparticle hybrid structures are prepared by forming Au and Pt nanoparticles on the sidewalls of single-walled carbon nanotubes. Reducing agent or catalyst-free electroless deposition, which purely utilizes the redox potential difference between Au3+, Pt2+, and the carbon nanotube, is the main driving force for this reaction. It is also shown that carbon nanotubes act as a template for wire-like metal structures. The successful formation of the hybrid structures is monitored by atomic

This review paper aims at a general introduction on up-to-date studies on the synthesis and properties of two-dimensional atomic layers of molybdenum disulphide, along with a brief overview on the bulk and three polytypes.

Polyamidoamine (PAMAM) dendrimers are used as carriers to deliver complexed Fe(Ill) ions uniformly onto silicon oxide substrates for the formation of iron oxide nanoparticles with,a narrow diameter in the range of 1-2 nm. Chemical vapor deposition (CVD) synthesis with these nanoparticles affords single-walled carbon nanotubes (SWNTs) with a diameter distribution in the range of 1-2 run, much narrower than that for SWNTs grown from commonly used powder-supported catalyst (1-5 nm) and from artific

A novel way to grow MoS2 on a large scale with uniformity and in desired patterns is developed. We use Au film as a catalyst on which [Mo(CO)6 ] vapor decomposes to form a Mo-Au surface alloy that is an ideal Mo reservoir for the growth of atomic layers of MoS2 . Upon exposure to H2 S, this surface alloy transforms into a few layers of MoS2 , which can be isolated and transferred on an arbitrary substrate. By simply patterning Au catalyst film by conventional lithographic techniques, MoS2 atomic

Metal catalyst-free growth of large scale single layer graphene film on a sapphire substrate by a chemical vapor deposition (CVD) process at 950 °C is demonstrated. A top-gated graphene field effect transistor (FET) device is successfully fabricated without any transfer process. The detailed growth process is investigated by the atomic force microscopy (AFM) studies.

Direct growth of a single to a few layers of graphene on a germanium nanowire (Gr/Ge NW; see picture) was achieved by a metal-catalyst-free chemical vapor deposition (CVD) process. The Gr/Ge NW was used as anode in a lithium ion battery. This material has a specific capacity of 1059 mA h g(-1) at 4.0 C, a long cycle life over 200 cycles, and a high capacity retention of 90%.

Novel p-type semiconductors can be found in these extraordinary comb structures. The GeSe combs are selectively formed by a vaporization–condensation–recrystallization (VCR) process using bulk GeSe powder as the precursor source. They have a flat body plate part and extended wire finger parts, both of which have identical crystal structures. The GeSe comb field-effect transistor device displays both p-type semiconducting and photo-switching behavior. Detailed facts of importance to specialist re

Geometrically defined C60 self-assembled disks, wires and dots have been systematically obtained via a solution drop-drying process at room temperature; during this process, we discovered that there is a critical correlation between the geometry of the solvent and the final geometry of the self-assembled C60 structure.

A direct and metal layer-free growth of flat graphene pads on exfoliated hexagonal boron nitride substrate (h-BN) are demonstrated by atmospheric chemical vapour deposition (CVD) process. Round shape with high flatness graphene pads are grown in high yield (∼95%) with a pad thickness of ∼0.5 nm and homogenous diameter.

Iron containing nanoparticles are found to spontaneously form on hydroxylated SiO2 substrates when immersed in a freshly mixed aqueous solution of FeCl3 and hydroxylamine. Upon calcination, a submonolayer of uniformly distributed iron oxide nanoparticles can be derived and used to catalyze the growth of single-walled carbon nanotubes by chemical vapor deposition. This simple method affords clean single-walled nanotube films on SiO2. The solution phase catalyst deposition approach allows for subm

Good solvent, poor solvent: A simple precipitation method enabled the spontaneous formation of homogeneous C70 cube crystals by self-crystallization in cavities of a good solvent (mesitylene) surrounded by a poor solvent (isopropyl alcohol, IPA; see picture). The enormously increased photoluminescence (PL) intensity of the C70 cube crystals relative to that of C70 powder was mainly attributed to the high crystallinity of the cubes. Detailed facts of importance to specialist readers are published

New jobs for disk jockeys: Single-crystalline C60 disks were selectively synthesized on an HOPG substrate by a vapor–solid process with C60 powder as the precursor. The photoluminescence intensity of the disks is much greater than that of thin films and powders. In photoconductivity measurements with a single disk the current was increased by about tenfold. These properties point to intriguing applications.

Despite potential advantages of covalent organic frameworks (COFs) in wide area applications, several limitations in conventional solvothermal synthesis, such as long reaction time and high reaction temperature, reduce reaction efficiency and prohibit technical processes for practical applications. Therefore, the development of a novel synthesis method that provides better reaction efficiency and spatial controllability has become a critical challenge. Herein, a photochemical synthesis of C 9 H

An atomically thin two-dimensional (2D) covalent organic framework (COF) was successfully synthesized via the photon-assisted imine condensation reaction within 1 h from the highly uniform and homogeneous precursor solution layer floating on the water surface. The polarity optimization of the precursor solution was the key step for the successful formation of the high-quality 2D COF because only the precursor solution consisting of polarity-controlled solvents allows ideal floating on the water