Electrochemical Performance of Layer-Structured Ni0.8Co0.1Mn0.1O2 Cathode Active Materials Synthesized by Carbonate Co-Precipitation.

The layered Ni-rich NiCoMn (NCM)-based cathode active material Li[NixCo(1-x)/2Mn(1-x)/2]O2 (x ≥ 0.6) has the advantages of high energy density and price competitiveness over an LiCoO2-based material. Additionally, NCM is beneficial in terms of its increasing reversible discharge capacity with the increase in Ni content; however, stable electrochemical performance has not been readily achieved because of the cation mixing that occurs during its synthesis. In this study, various layer-structured Li1.0[Ni0.8Co0.1Mn0.1]O2 materials were synthesized, and their electrochemical performances were investigated. A NiCoMnCO3 precursor, prepared using carbonate co-precipitation with Li2CO3 as the lithium source and having a sintering temperature of 850 °C, sintering time of 25 h, and metal to Li molar ratio of 1.00-1.05 were found to be the optimal parameters/conditions for the preparation of Li1.0[Ni0.8Co0.1Mn0.1]O2. The material exhibited a discharge capacity of 160 mAhg-1 and capacity recovery rate of 95.56% (from a 5.0-0.1 C-rate).

Facile Strategy for Mass Production of Pt Catalysts for Polymer Electrolyte Membrane Fuel Cells Using Low-Energy Electron Beam.

There are so many variables affecting the large-scale chemical synthesis of nanoparticles that mass production remains a challenge. Here, using a high-efficiency compact electron beam generator irradiating a low-energy electron beam, we fabricate carbon-supported Pt nanoparticles (Pt/C) in an open chamber to present the applicability of an electron beam to the mass production of metal nanocatalysts for polymer electrolyte membrane fuel cells (PEMFCs). The amount of dispersants (glycerol) and radical scavengers (isopropyl alcohol, IPA), the most important factors in the electron beam-induced fabrication process, is systematically controlled to find the conditions for the synthesis of the particle structure suitable for PEMFC applications. Furthermore, the effects of the structural changes on the electrochemical properties of the catalysts are thoroughly investigated. Through in-depth studies, it is clearly revealed that while dispersants control the nucleation step of monomers affecting the degree of dispersion of nanoparticles, radical scavengers with strong oxidizing power have an effect on the particle growth rate. Therefore, this study is expected to present the applicability of low-energy electron beam to the mass production of metal nanocatalysts for PEMFCs, and to provide insights into the fabrication of nanoparticles using low-energy electron beams.

Humidity-Sensitive Field Effect Transistor with In2O3 Nanoparticles as a Sensing Layer.

In this work, we investigate the humidity-sensing performance on a humidity-sensitive p-channel field effect transistor (FET) having a floating-gate (FG) and a control-gate (CG) placing horizontally each other. A sensing layer is formed onto a part of the CG and the O/N/O stack over the FG by inkjet-printing process. The printed ink is composed of indium oxide (In2O3. nanoparticles and dimethylformamide (HCON(CH3)2) as solvent. DC/Pulsed measurements are carried out by switching chamber ambience between dry and humid N2 at 25 °C. Pulsed measurement effectively alleviates the ID drift of the device. When the device is exposed to humidity, the |ID| is appreciably decreased in the p-channel FET-type sensor, since H2O molecules act as an electron donor. The sensitivity of the sensor increases with increasing relative humidity up to about 68% and decreases with further increasing relative humidity.

Observation of physisorption in a high-performance FET-type oxygen gas sensor operating at room temperature.

Oxygen (O2) sensors are needed for monitoring environment and human health. O2 sensing at low temperature is required, but studies are lacking. Here we report, for the first time, that the performance of a field effect transistor (FET)-type O2 sensor operating at 25 °C was improved greatly by a physisorption sensing mechanism. The sensing material was platinum-doped indium oxide (Pt-In2O3) nanoparticles formed by an inkjet printer. The FET-type sensor showed excellent repeatability under a physisorption mechanism and showed much better sensing performance than a resistor-type sensor fabricated on the same wafer at 25 °C. The sensitivity of the sensor increased with increasing Pt concentration up to ∼10% and decreased with further increasing Pt concentration. When the sensing temperature reached 140 °C, the sensing mechanism of the sensor changed from physisorption to chemisorption. Interestingly, the pulse pre-bias before the read bias affected chemisorption but had no effect on physisorption.

Analysis of Current Fluctuation Due to Trap and Percolation Path in Nano-Scale Bulk FinFET.

An electron in the channel can be trapped into the trap inside gate oxide and detrapped into the channel, resulting in the fluctuation in drain current. To investigate the drain current fluctuation (ΔI(D)) caused by trapping/detrapping of an electron in 22 nm bulk FinFET, 3-D device simulation was performed extensively. The ΔI(D) is changed by changing the position of the trap in the gate oxide along the surface of fin body. In the bulk FinFET, the trap located near the center of side surface of the fin body gives the larger ΔI(D) compared to those of the traps located at the top center, top corner, and side bottom. At a fixed trap position, the shallower trap depth (x(T)) from the interface between the gate oxide and the fin body gives the lager ΔI(D). With decreasing fin width (W(fin)) and fin height (H(fin)), the ΔI(D) increases. Especially, decreasing H(fin) increases ΔI(D) significantly. As the trap is close to a percolation path, the ΔI(D) also increases.

Water-soluble thin film transistors and circuits based on amorphous indium-gallium-zinc oxide.

This paper presents device designs, circuit demonstrations, and dissolution kinetics for amorphous indium-gallium-zinc oxide (a-IGZO) thin film transistors (TFTs) comprised completely of water-soluble materials, including SiNx, SiOx, molybdenum, and poly(vinyl alcohol) (PVA). Collections of these types of physically transient a-IGZO TFTs and 5-stage ring oscillators (ROs), constructed with them, show field effect mobilities (∼10 cm2/Vs), on/off ratios (∼2×10(6)), subthreshold slopes (∼220 mV/dec), Ohmic contact properties, and oscillation frequency of 5.67 kHz at supply voltages of 19 V, all comparable to otherwise similar devices constructed in conventional ways with standard, nontransient materials. Studies of dissolution kinetics for a-IGZO films in deionized water, bovine serum, and phosphate buffer saline solution provide data of relevance for the potential use of these materials and this technology in temporary biomedical implants.

Development of target-specific multimodality imaging agent by using hollow manganese oxide nanoparticles as a platform.

A platform protocol developed based on the hollow manganese oxide nanoparticles provided multimodal diagnostic agents, which allow the selectively detect vulva cancer with T(1)-weighted in vivo MRI.

Reductive dissolution of Fe3O4 facilitated by the Au domain of an Fe3O4/Au hybrid nanocrystal: formation of a nanorattle structure composed of a hollow porous silica nanoshell and entrapped Au nanocrystal.

The Fe(3)O(4) grain of a Fe(3)O(4)/Au hybrid nanocrystal encapsulated in a silica nanosphere was rapidly and exclusively dissolved through a reductive process facilitated by the attached Au grain, resulting in the formation of a nanorattle structure which has utility as a nanoreactor to template the growth of nanocrystals inside the cavity.

Synthesis of Fe(3)O(4)/PdO heterodimer nanocrystals in silica nanospheres and their controllable transformation into Fe(3)O(4)/Pd heterodimers and FePd nanocrystals.

The thermal annealing of silica nanospheres encapsulating Fe(3)O(4) nanocrystals and Pd(2+) complexes led to the formation of heterodimers consisting of Fe(3)O(4) and PdO nanoparticles encapsulated in a silica shell, allowing for their controllable transformation into either Fe(3)O(4)/Pd heterodimers or FePd alloy nanocrystals through a solid state reduction process.