A5060697928- Graphene research and applications
- 2D Materials and Applications
- MXene and MAX Phase Materials
- Carbon Nanotubes in Composites
- Advancements in Battery Materials
- Conducting polymers and applications
- ZnO doping and properties
- Supercapacitor Materials and Fabrication
- Gas Sensing Nanomaterials and Sensors
- Advanced Sensor and Energy Harvesting Materials
- Quantum Dots Synthesis And Properties
- Electrocatalysts for Energy Conversion
- Advanced Photocatalysis Techniques
- Particle Accelerators and Free-Electron Lasers
- Chalcogenide Semiconductor Thin Films
- Particle accelerators and beam dynamics
- Advanced Battery Materials and Technologies
- Nanowire Synthesis and Applications
- Molecular Junctions and Nanostructures
- Graphene and Nanomaterials Applications
- CO2 Reduction Techniques and Catalysts
- Ga2O3 and related materials
- Advanced battery technologies research
- Ferroelectric and Piezoelectric Materials
- Perovskite Materials and Applications
Sungkyunkwan University
2015-2024
Korea Institute of Science and Technology
2003-2024
Korea Advanced Institute of Science and Technology
2024
Pusan National University
2005-2024
Korea Research Institute of Chemical Technology
2024
Lawrence Berkeley National Laboratory
2024
Gachon University
2023-2024
Korea Institute of Materials Science
2021-2024
Kumoh National Institute of Technology
2009-2022
SK Group (South Korea)
2022
Abstract The conductivity of graphite oxide films is modulated using reducing agents. It found that the sheet resistance film reduced sodium borohydride (NaBH 4 ) much lower than hydrazine (N 2 H ). This attributed to formation CN groups in N case, which may act as donors compensating hole carriers oxide. In case NaBH reduction, interlayer distance first slightly expanded by intermediate boron complexes and then contracted gradual removal carbonyl hydroxyl along with complexes. fabricated...
Graphene is a distinct two-dimensional material that offers wide range of opportunities for membrane applications because ultimate thinness, flexibility, chemical stability, and mechanical strength. We demonstrate few- several-layered graphene oxide (GO) sheets can be engineered to exhibit the desired gas separation characteristics. Selective diffusion achieved by controlling flow channels pores via different stacking methods. For layered (3- 10-nanometer) GO membranes, tunable transport...
Large-area, few-layer graphene is grown on a poly-nickel substrate using optimized CVD conditions. High temperature, short growth time, and an optimal gas mixing ratio (C2H2/H2 = 2/45) are found to be necessary synthesize highly crystalline grapheme, which may find applications in electronic devices. The wrinkles that observed under all conditions proposed formed by two processes.
As research on secondary batteries becomes important, interest in analytical methods to examine the condition of is also increasing. Among these methods, electrochemical impedance spectroscopy (EIS) method one most attractive diagnostic techniques due its convenience, quickness, accuracy, and low cost. However, since obtained spectra are complicated signals representing several elements, it necessary understand whole environment for a meaningful analysis. Based understanding system, circuit...
Hexagonal boron nitride (h-BN) has received a great deal of attention as substrate material for high-performance graphene electronics because it an atomically smooth surface, lattice constant similar to that graphene, large optical phonon modes, and electrical band gap. Herein, we report the large-scale synthesis high-quality h-BN nanosheets in chemical vapor deposition (CVD) process by controlling surface morphologies copper (Cu) catalysts. It was found morphology control Cu foil is much...
Transparent flexible charge-generating piezoelectric nanodevices are developed. The resulting integrated nanodevice generates a noticeable current when it is pushed by application of an external load. Piezoelectric ZnO nanorod-based with embossed PdAu top electrodes produce the highest output density approximately 10 μA cm−2 at load 0.9 kgf.
One unique feature in parallel three-phase converters is a potential zero-sequence circulating current. To avoid the current, most present technology uses an isolation approach, such as transformers or separate power supplies. This paper proposes system where individual connect both AC and DC sides directly without additional passive components to reduce size cost of overall system. In this case, control current becomes important objective converter design. paper: (1) develops averaged model...
We report that highly crystalline graphene can be obtained from well-controlled surface morphology of the copper substrate. Flat was prepared by using a chemical mechanical polishing method. At early growth stage, density nucleation seeds polished Cu film much lower and domain sizes flakes were larger than those unpolished film. later these domains stitched together to form monolayer graphene, where orientation each crystal unexpectedly not different other. also found grain boundaries...
Supercapacitors with porous carbon structures have high energy storage capacity. However, the nature of electrode, composed mainly nanotubes (CNTs) and graphene oxide (GO) derivatives, negatively impacts volumetric electrochemical characteristics supercapacitors because poor packing density (<0.5 g cm(-3)). Herein, we report a simple method to fabricate highly dense vertically aligned reduced (VArGO) electrodes involving hand-rolling cutting processes. Because their opened-edge structure,...
Fully rollable transparent nanogenerators have been developed using chemical vapor deposition-grown large-scale graphene sheets as electrodes and piezoelectric ZnO-nanorod arrays. The electrical structural stability of the with excellent charge scavenging performance under external mechanical loads such bending rolling shows that graphene-based are suitable for self-powered device applications. Detailed facts importance to specialist readers published "Supporting Information". Such documents...
We propose a new method of layer-by-layer (LbL) doping thin graphene films. Large area monolayer was synthesized on Cu foil by using the chemical vapor deposition method. Each layer transferred polyethylene terephthalate substrate followed salt-solution casting, where whole process repeated several times to get LbL-doped layers. With this method, sheet resistance significantly decreased up ∼80% with little sacrifice in transmittance. Unlike samples fabricated topmost doping, our sample shows...
Chemically bonded graphene/carbon nanotube composites as flexible supercapacitor electrode materials are synthesized by amide bonding. Carbon nanotubes attached along the edges and onto surface of graphene act spacers to increase electrolyte-accessible area. Our lamellar structure electrodes demonstrate largest volumetric capacitance (165 F cm-3) ever shown carbon-based electrodes.
Abstract Enhanced performance of an inverted‐type polymer solar cell is reported by controlling the surface energy a zinc oxide (ZnO) buffer layer, on which photoactive layer composed polymer:fullerene‐derivative bulk heterojunction formed. With approach based mixed self‐assembled monolayer, ZnO can be controlled between 40 mN m −1 and 70 with negligible changes in its work function. For given range power conversion efficiency increases from 3.27% to 3.70% through enhanced photocurrents. The...
It is essential to control the electronic structure of graphene in order apply films for use electrodes. We have introduced chemical dopants that modulate properties few-layer synthesized by vapor deposition. The work function, sheet carrier density, mobility, and resistance these were systematically modulated reduction potential values dopants. further demonstrated power generation a nanogenerator was strongly influenced choice electrode with modified function. off-current well quenched...
Li ion battery (LIB) is one of the most remarkable energy storage devices currently available in various applications. With a growing demand for high-performance batteries, role electrochemical analysis especially, electrode reactions are becoming very important and crucial. Among analytical methods, cyclic voltammetry (CV) versatile widely used many fields electrochemistry. Through CV, it possible to know factors affecting reaction voltage reversibility, furthermore, quantitative on Li+...
Direct chemical vapor deposition (CVD) growth of single-layer graphene on CVD-grown hexagonal boron nitride (h-BN) film can suggest a large-scale and high-quality graphene/h-BN hybrid structure with defect-free interface. This sequentially grown shows better electronic properties than that graphene/SiO2 or transferred h-BN film, suggests new promising template for device fabrication. As service to our authors readers, this journal provides supporting information supplied by the authors. Such...
This review summarizes organic molecule-based electrode materials for rechargeable batteries.
We investigated the modulation of optical properties single-walled carbon nanotubes (SWCNTs) by AuCl 3 doping. The van Hove singularity transitions (E 11 (S), E 22 (M)) in absorption spectroscopy disappeared gradually with an increasing doping concentration and a new peak appeared at high concentration. work function was downshifted up to 0.42 eV strong charge transfer from SWCNTs level p-doping. propose that this large shift forces Fermi be located deep valence band, i.e., highly...
Easily soluble expanded graphite is synthesized in a one-step exfoliation process that can be used for the lowcost mass production of graphene various applications because simplicity and speed process. The obtained sufficiently to dispersed aqueous solutions with an ordinary surfactant organic solvents.
Various viologens have been used to control the doping of single-walled carbon nanotubes (SWCNTs) via direct redox reactions. A new method extracting neutral viologen (V(0)) was introduced using a biphase toluene and viologen-dissolved water. reductant sodium borohydride transferred positively charged (V(2+)) into V(0), where reduced V(0) separated with high separation yield. This solution dropped on nanotube transistors investigate effect CNTs. With concentration 3 mM, all p-type CNT were...