Young In Lee

Platinum (Pt)-doped SnO2 nanopowders were prepared by a new doping method which controls the surface charge by controlling the pH. Individual Pt particles were homogenously doped on the surface of the SnO2 nanoparticles at pH 6. Subsequently, a heat treatment was conducted in a hydrogen atmosphere to remove contaminants and to increase the number of oxygen vacancies of the SnO2 nanopowders. To recognize the sensitivity of the powders, Pt-doped SnO2 gas sensors were fabricated using a dispensing

Macro-mesoporous Pt/alumina catalysts were synthesized by the sol-gel process with the assistance of a PS colloidal crystal template to improve the catalytic activity of hydrogen oxidation. Macropores in catalysts improve hydrogen gas diffusion and enhance the accessibility of hydrogen gas to the center of the catalyst. The diffusion coefficients of hydrogen gas in macro- and mesopores were theoretically calculated. The effect of macropores on exothermic properties induced by hydrogen oxidation

In this study, we demonstrated a simple and eco-friendly method, including mechanical polishing and attrition milling processes, to recycle sputtered indium tin oxide targets to indium tin oxide nanopowders and targets for sputtered transparent conductive films. The utilized indium tin oxide target was first pulverized to a powder of sub- to a few- micrometer size by polishing using a diamond particle coated polishing wheel. The calcination of the crushed indium tin oxide powder was carried out

SnO2 nanotubes were successfully synthesized using an electrospinning technique followed by calcination in air. The nanotubes were the single phase nature of SnO2 and consisted of approximately 14 nm nanocrystals. SEM and TEM characterizations demonstrated that uniform hollow fibers with an average outer diameter of around 124 nm and wall thickness of around 25 nm were successfully obtained. As anode materials for lithium ion batteries, the SnO2 nanotubes exhibited excellent cyclability and reve

Metal nanowires can be coated on various substrates to create transparent conducting films that can potentially replace the dominant transparent conductor, indium tin oxide, in displays, solar cells, organic light-emitting diodes, and electrochromic windows. One issue with these metal nanowire based transparent conductive films is that the resistance between the nanowires is still high because of their low aspect ratio. Here, we demonstrate high-performance transparent conductive films with silv

In this study, an oxygen plasma treatment was used as a low temperature debinding method to form a conductive copper feature on a flexible substrate using a direct printing process. To demonstrate this concept, conductive copper patterns were formed on polyimide films using a copper nanoparticle-based paste with polymeric binders and dispersing agents and a screen printing method. Thermal and oxygen plasma treatments were utilized to remove the polymeric vehicle before a sintering of copper nano

A new High Frequency Induction Heating (HFIH) process has been developed to fabricate dense Al2O3 reinforced with Fe-Ni magnetic metal dispersion particles. The process is based on the reduction of metal oxide particles immediately prior to sintering. The synthesized Al2O3/Fe-Ni nanocomposite powders were formed directly from the selective reduction of metal oxide powders, such as NiO and Fe2O3. Dense Al2O3/Fe-Ni nanocomposite was fabricated using the HFIH method with an extremely high heating r

Single crystalline Cu nanowires with controlled diameters and aspect ratios have been synthesized using electrochemical deposition within confined nanochannels of a porous anodic aluminium oxide(AAO) template. The diameters of nano-sized cylindrical pores in AAO template were adjusted by controlling the anodization conditions. Cu nanowires with diameters of approximately 38, 99, 274 nm were synthesized by the electrodeposition using the AAO templates. The crystal structure, morphology and micros

In this study, we successfully synthesized a nano-sized lanthanum-modified lead-titanate (PLT)powder with a perovskite structure using a high-energy mechanochemical process (MCP). In addition, the sintering behavior of synthesized PLT nanopowder was investigated and the sintering temperature that can make the full dense PLT specimen decreased to below 1050oC by using Bi2O3 powder as sintering agent. The pure PLT phase of perovskite structure was formed after MCP was conducted for 4 h and the ave

FeNi alloy nanofibers have been prepared by an electrospinning process followed by air-calcination and H2reduction to develop electromagnetic (EM) wave absorbers in the giga-hertz (GHz) frequency range. The thermal behavior and phase and morphology evolution in the synthetic processes were systematically investigated. Through the heat treatments of calcination and H2 reduction, as-spun PVP/FeNi precursor nanofiber has been stepwise transformed into nickel iron oxide and FeNi phases but the fibro