A5003077900- Electronic and Structural Properties of Oxides
- Semiconductor materials and devices
- Semiconductor materials and interfaces
- Electrocatalysts for Energy Conversion
- Gas Sensing Nanomaterials and Sensors
- ZnO doping and properties
- Advanced Memory and Neural Computing
- Transition Metal Oxide Nanomaterials
- Chalcogenide Semiconductor Thin Films
- Magnetic and transport properties of perovskites and related materials
- CO2 Reduction Techniques and Catalysts
- Model Reduction and Neural Networks
- Atmospheric chemistry and aerosols
- Generative Adversarial Networks and Image Synthesis
- Neuroscience and Neural Engineering
- Topological Materials and Phenomena
- Quantum Dots Synthesis And Properties
- Multiferroics and related materials
- Advanced Condensed Matter Physics
- Force Microscopy Techniques and Applications
- Ultrasound and Hyperthermia Applications
- Ferroelectric and Piezoelectric Materials
- Bone Tissue Engineering Materials
- Ga2O3 and related materials
- Acute Kidney Injury Research
Yonsei University
2021-2023
Hyundai Motor Group (South Korea)
2023
Jeonbuk National University
2021-2022
Korea Advanced Institute of Science and Technology
2021
Institute for Basic Science
2017-2020
Chungnam National University
2019-2020
Chungnam National University Hospital
2020
Sungkyunkwan University
2018-2020
Seoul National University
2014-2018
Korea Institute of Science and Technology
2011-2018
Oxygen evolution reaction (OER) is the key in electrochemical processes, such as water splitting, metal-air batteries, and solar fuel production. Herein, we developed a facile chemical solution deposition method to prepare highly active Co3O4 thin film electrode for OER, showing low overpotential of 377 mV at 10 mA/cm(2) with good stability. An optimal loading ethyl cellulose additive precursor was found be essential morphology control thus its electrocatalytic activity. Our results also...
Although the particle phase state is an important property, there scant information on it, especially, for real-world aerosols. To explore of fine mode aerosols (PM2.5) in two megacities, Seoul and Beijing, we collected PM2.5 filter samples daily from Dec 2020 to Jan 2021. Using optical microscopy combined with poke-and-flow technique, states bulk as a function relative humidity (RH) were determined compared ambient RH ranges cities. was found be liquid semisolid but mostly solid Beijing....
In-vehicle network (IVN) technologies are changing corresponding to the rapidly increasing demand in autonomous driving and vehicle electrification. Due increase real-time data generated from control modules sensors, controller area networks (CANs) have a heavier burden satisfy strict delay bounds. Therefore, CAN with flexible rate (CAN-FD) Automotive Ethernet (AE) drawn attention as promising IVNs. This paper provides an overview of IVN transmission protocols, time characteristics, analysis...
In tissue engineering, biocompatible scaffolds are used as 3D cell niches to provide a similar environment that of native for seeded cells regenerate the target tissue. When engineering bone tissue, high mechanical strength and calcium phosphate composition essential factors consider. this study, we fabricated composite composed synthetic polymers (polycaprolactone (PCL) poly (vinyl alcohol) (PVA)), natural (gelatin collagen) bioceramic (hydroxyapatite; HA) engineering. The were enhance...
The electrocatalytic property of a flat or an oxide-derived nanostructure Au electrode was investigated using surface sensitive analysis methods such as impedance spectroscopy and Kelvin probe force microscopy (KPFM) when electrochemical conversion carbon dioxide (CO2) to monoxide (CO) performed with either KHCO3- NaHCO3-based neutral electrolyte. A strong dependence on the cation electrolyte exhibited surface. CO selectivity capacitance dispersion are significantly higher KHCO3 On other...
Abstract The formation of a nanostructure is popular strategy for catalyst applications because it can generate new surfaces that significantly improve the catalytic activity and durability catalysts. However, increase in surface area resulting from nanostructuring does not fully explain substantial improvement properties CO 2 electroreduction reaction, underlying mechanisms have yet been understood. Here, based on combination extended X‐ray absorption fine structure analysis, photoelectron...
Atmospheric ammonia (NH3) plays a critical role in PM2.5 pollution. Data on atmospheric NH3 are scanty; thus, the of formation ammonium ions (NH4+) various environments is understudied. Herein, we measured concentrations NH3, PM2.5, and its water-soluble SO42−, NO3−, NH4+ (SNA) at an urban site Jeonju, South Korea from May 2019 to April 2020. During measurement period, average were 10.5 ± 4.8 ppb 24.0 12.8 μg/m3, respectively, SNA amounted 4.3 3.1, 4.4 4.9, 1.6 1.8 respectively. A...
We investigated the long-lasting hydrophilic behavior of a Si-incorporated diamond-like carbon (Si-DLC) film by varying Si fraction in DLC matrix through oxygen and nitrogen plasma surface treatments. The wetting water droplets on pure Si-DLC with or treatment revealed that element oxygen-plasma-treated films played major role maintaining angle <10° for 20 days ambient air. nanostructured patterns roughness ∼10 nm evolved because selective etching film, where chemical component Si-Ox bond...
Transport and Kelvin probe force microscopy measurements were simultaneously conducted on epitaxial VO2 thin films. The sample's work function abruptly dropped from 4.88 eV to 4.70 during heating 333 K 353 K, suggesting a significant change in its electronic band structure spanning the metal insulator transition. showed nearly no statistical deviation across film's surface transition, likely due bending at boundaries of small domains. Resistance profiles confirmed that local corresponded...
Abstract Pd nanoparticle (NP) coated LaAlO 3 /SrTiO (LAO/STO) heterointerface exhibits more notable conductance ( G ) change while varying the ambient gas (N 2 , H /N and O illuminating with UV light (wavelength: 365 nm) than a sample without NPs. Simultaneous Kelvin probe force microscopy transport measurements reveal close relationships between surface work function W of samples. Quantitative analyses suggest that adsorption/desorption-mediated reaction redox, resulting in band-alignment...
OPV HTL fluorination alters not only the electronic properties but also complex refractive indices.
Fluorinated additives in PEDOT:PSS slow organic solar cell degradation and the underlying mechanisms potentials are discussed.
The temperature dependent electrical properties of Ag Schottky contacts to a-plane bulk ZnO single crystal were investigated in the range 100–300 K. variation barrier heights was described by a double Gaussian distribution with two different regions 200–300 and 100–180 modified Richardson plot K produced constant 29 A cm−2 K−2 which is similar theoretical value 32 for n-type ZnO, indicating that inhomogeneous height thermionic emission model can explain current transport well this region....
We investigated the surface potential of TiO2 single crystals using scanning probe microscopy (SPM) under different gas environment. The SPM tip-induced electrical stress resulted in reversal potential, Vsurf, polarity only H2/Ar (ΔVsurf = 0.30 eV) and not Ar O2. Quantitative measurement influence ambient on led us to develop a model where adsorbed oxygen molecules vacancies interact change their relative concentration leading TiO2. These results will give insights into ambient-dependent...
The chemical composition change of Ni and Fe on a cratered stainless steel surface as result electrochemical oxidation leads to significantly enhanced water properties in neutral electrolyte.
A nanoscale Schottky diode using Pt nanodisks on a Nb-doped SrTiO3 (Nb:STO) single crystal was fabricated, and resistive switching (RS) demonstrated with conductive atomic force microscopy at ultrahigh vacuum. disks diameters the order of 10 nm were formed colloidal self-assembled patterns silica nanospheres, followed by evaporation layers Nb:STO crystal. Here we show that reproducible bipolar RS behavior Pt/Nb:STO junction achieved utilizing local current-voltage spectroscopy. The...
Abstract With the advanced investigations into low-dimensional systems, it has become essential to find materials having interesting lattices that can be exfoliated down monolayer. One particular important structure is a kagome lattice with its potentially diverse and vibrant physics. We report van-der-Waals material, Pd 3 P 2 S 8, several unique properties such as an intriguing flat band. The band shown arise from possible compact-localized state of all five 4d orbitals Pd. diamagnetic...
Hexagonal manganites are multiferroic materials with two highly-dissimilar phase transitions: a ferroelectric transition (from P63/mmc to P63cm) at temperature higher than 1000 K and an antiferromagnetic TN=65 - 130 K. Despite its critical relevance the intriguing domain physics, details of yet not well known date primarily because ultra-high temperature. Using high-temperature X-ray diffraction experiments, we show that is single abrupt order R-Op displacement primary parameter. This...