A5082813627- Graphene research and applications
- 2D Materials and Applications
- MXene and MAX Phase Materials
- Advancements in Battery Materials
- Diamond and Carbon-based Materials Research
- Semiconductor materials and devices
- Aluminum Alloys Composites Properties
- Microstructure and mechanical properties
- Graphene and Nanomaterials Applications
- Chalcogenide Semiconductor Thin Films
- Electrocatalysts for Energy Conversion
- Carbon Nanotubes in Composites
- ZnO doping and properties
- Supercapacitor Materials and Fabrication
- Aluminum Alloy Microstructure Properties
- Perovskite Materials and Applications
- Electronic and Structural Properties of Oxides
- Electron and X-Ray Spectroscopy Techniques
- Quantum Dots Synthesis And Properties
- Advanced Photocatalysis Techniques
- Advanced Electron Microscopy Techniques and Applications
- Transition Metal Oxide Nanomaterials
- Advanced Memory and Neural Computing
- Molecular Junctions and Nanostructures
- Gas Sensing Nanomaterials and Sensors
Ulsan National Institute of Science and Technology
2016-2025
Institute for Basic Science
2016-2025
Government of the Republic of Korea
2018-2021
Ulsan College
2015-2018
Lawrence Berkeley National Laboratory
2005-2012
University of California, Berkeley
2006-2012
Los Alamos National Laboratory
2008
National Cheng Kung University
2007
Southern California University for Professional Studies
2006
University of Southern California
2002-2006
The local atomic structure of graphene oxide (GO) and reduced annealed (raGO) is determined via ultra-high-resolution transmission electron microscopy. We find that the proposed desired return to from GO not possible through synthetic route employed. detailed GO, previously unknown, revealed as mottled, with few square nanometer graphitic regions separated by highly oxidized regions.
We present a novel method for synthesizing graphene sheets in the gas phase using substrate-free, atmospheric-pressure microwave plasma reactor. Graphene were synthesized by passing liquid ethanol droplets into an argon plasma. The characterized transmission electron microscopy, energy loss spectroscopy, Raman and diffraction. prove that can be created without three-dimensional materials or substrates demonstrate possible avenue to large-scale synthesis of graphene.
We report direct mapping of the grains and grain boundaries (GBs) large-area monolayer polycrystalline graphene sheets, at large (several micrometer) single-atom length scales. Global GB is performed using electron diffraction in scanning transmission microscopy (STEM) or dark-field imaging conventional TEM. Additionally, we employ aberration-corrected TEM to extract images local atomic arrangements GBs, which reveal alternating pentagon−heptagon structure along high-angle GBs. Our findings...
The manipulation of the bandgap graphene by various means has stirred great interest for potential applications. Here we show that treatment with xenon difluoride produces a partially fluorinated (fluorographene) covalent C−F bonding and local sp3-carbon hybridization. material was characterized Fourier transform infrared spectroscopy, Raman electron energy loss photoluminescence near edge X-ray absorption spectroscopy. These results confirm structural features fluorographane 3.8 eV, close...
Hexagonal boron nitride (h-BN) is gaining significant attention as a two-dimensional dielectric material, along with graphene and other such materials. Herein, we demonstrate the growth of highly crystalline, single-layer h-BN on Pt foil through low-pressure chemical vapor deposition method that allowed to be grown over wide area (8 × 25 mm(2)). An electrochemical bubbling-based was used transfer layer from onto an arbitrary substrate. This foil, which not consumed during process, recycled...
Abstract The high-volume synthesis of two-dimensional (2D) materials in the form platelets is desirable for various applications. While water considered an ideal dispersion medium, due to its abundance and low cost, hydrophobicity platelet surfaces has prohibited widespread use. Here we exfoliate 2D directly pure without using any chemicals or surfactants. In order disperse water, elevate temperature sonication bath, introduce energy via dissipation sonic waves. Storage stability greater...
The folding of paper, hide, and woven fabric has been used for millennia to achieve enhanced articulation, curvature, visual appeal intrinsically flat, two-dimensional materials. For graphene, an ideal material, may transform it complex shapes with new distinct properties. Here, we present experimental results that folded structures in termed grafold, exist, their formations can be controlled by introducing anisotropic surface curvature during graphene synthesis or transfer processes. Using...
The high cost of the platinum-based cathode catalysts for oxygen reduction reaction (ORR) has impeded widespread application polymer electrolyte fuel cells. We report on a new family non-precious metal based ordered mesoporous porphyrinic carbons (M-OMPC; M = Fe, Co, or FeCo) with surface areas and tunable pore structures, which were prepared by nanocasting silica templates metalloporphyrin precursors. FeCo-OMPC catalyst exhibited an excellent ORR activity in acidic medium, higher than other...
Abstract The most efficient electrocatalyst for the hydrogen evolution reaction (HER) is a Pt‐based catalyst, but its high cost and nonperfect efficiency hinder wide‐ranging industrial/technological applications. Here, an of both ruthenium (Ru) single atoms (SAs) N‐doped‐graphitic(G N )‐shell‐covered nitrided‐Ru nanoparticles (NPs) (having Ru‐N x shell) embedded on melamine‐derived G matrix { 1 : [Ru(SA)+Ru(NP)@RuN @G ]/G }, which exhibits superior HER activity in acidic basic media,...
The practical use of graphene in consumer electronics has not been demonstrated since the size, uniformity, and reliability problems are yet to be solved satisfy industrial standards. Here we report mass-produced films synthesized by hydrogen-free rapid thermal chemical vapor deposition (RT-CVD), roll-to-roll etching, transfer methods, which enabled faster larger production homogeneous over 400 × 300 mm(2) area with a sheet resistance 249 ± 17 Ω/sq without additional doping. properties...
By plasma-enhanced chemical vapor deposition, a molybdenum disulfide (MoS2 ) thin film is synthesized directly on wafer-scale plastic substrate at below 300 °C. The carrier mobility of the films 3.74 cm(2) V(-1) s(-1) . Also, humidity successfully detected with MoS2 -based sensors fabricated flexible substrate, which reveals its potential for sensing devices.
The effective synthesis of two-dimensional transition metal dichalcogenides alloy is essential for successful application in electronic and optical devices based on a tunable band gap. Here we show process Mo1-xWxS2 using sulfurization super-cycle atomic layer deposition Mo1-xWxOy. Various spectroscopic microscopic results indicate that the synthesized alloys have complete mixing Mo W atoms gap by systematically controlled composition number. Based this, synthesize vertically...
Abstract 2D transition metal dichalcogenides (TMDs) have attracted much attention for their gas sensing applications due to superior responsivity at typical room temperature. However, low power consumption and reliable selectivity are the two main requirements sensors be applicable in future electronic devices. Herein, a p‐type (WSe 2 /WS ) n‐type (MoS /WSe photovoltaic self‐powered sensor is demonstrated using TMD heterostructures first time. The operated by effect of heterostructures,...
Crystallographic direction of black phosphorus can be determined from polarized optical microscopy and Raman spectroscopy.
Abstract Low‐energy density has long been the major limitation to application of supercapacitors. Introducing topological defects and dopants in carbon‐based electrodes a supercapacitor improves performance by maximizing gravimetric capacitance per mass electrode. However, main mechanisms governing this improvement are still unclear. We fabricated planar from CVD‐derived single‐layer graphene with deliberately introduced nitrogen controlled concentrations known configurations, estimate...
In this work, we designed a novel CuO/Al 2 CuO 4 catalyst by phase and interphase engineering approach, which enables the electrochemical conversion of carbon dioxide to ethylene with ultrahigh activity selectivity.