Showing papers on "Ternary operation published in 2009"

Atomic level structure in multicomponent bulk metallic glass.

Abstract: The atomic-level structure of a representative ternary Cu-Zr-Al bulk metallic glass (BMG) has been resolved. Cu- (and Al-) centered icosahedral clusters are identified as the basic local structural motifs. Compared with the Cu-Zr base binary, a small percentage of Al in the ternary BMG leads to dramatically increased population of full icosahedra and their spatial connectivity. The stabilizing effect of Al is not merely topological, but also has its origin in the electronic interactions and bond shortening.

Photovoltaic devices employing ternary PbSxSe1-x nanocrystals.

Abstract: We report solar cells based on highly confined nanocrystals of the ternary compound PbSxSe1-x. Crystalline, monodisperse alloyed nanocrystals are obtained using a one-pot, hot injection reaction. Rutherford back scattering and energy filtered transmission electron microscopy suggest that the S and Se anions are uniformly distributed in the alloy nanoparticles. Photovoltaic devices made using ternary nanoparticles are more efficient than either pure PbS or pure PbSe based nanocrystal devices.

Recent Progress in Theoretical Prediction, Preparation, and Characterization of Layered Ternary Transition-Metal Carbides

Abstract: Layered ternary carbides contain alternative stacking of structural slabs in the unit cells. Many mechanical and structural features are inherited with respect to their binary carbide counterparts, and some novel properties also appear because of new chemical bonds and atomic coordination at the boundaries of different slabs. In this review, we highlight important recent achievements that focus on theoretical prediction, microstructure characterization preparation, and macroscopic properties of newly developed layered ternary transition-metal carbides. These results provide insights into understanding the relationship between the structure (including crystal structure, chemical bonding, and microstructure) and the properties of these layered ternary carbides and further highlight their technological applications as high-temperature and ultrahigh-temperature structural materials.

Phase transformation of biphasic Cu2S-CuInS2 to monophasic CuInS2 nanorods.

Abstract: We synthesized wurtzite CuInS2 nanorods (NRs) by colloidal solution-phase growth. We discovered that the growth process starts with nucleation of Cu2S nanodisks, followed by epitaxial overgrowth of CuInS2 NRs onto only one face of Cu2S nanodisks, resulting in biphasic Cu2S−CISu heterostructured NRs. The phase transformation of biphasic Cu2S−CuInS2 into monophasic CuInS2 NRs occurred with growth progression. The observed epitaxial overgrowth and phase transformation is facile for three reasons. First, the sharing of the sulfur sublattice by the hexagonal chalcocite Cu2S and wurtzite CuInS2 minimizes the lattice distortion. Second, Cu2S is in a superionic conducting state at the growth temperature of 250 °C wherein the copper ions move fluidly. Third, the size of the Cu2S nanodisks is small, resulting in fast phase transformation. Our results provide valuable insight into the controlled solution growth of ternary chalcogenide nanoparticles and will aid in the development of solar cells using ternary I−III−V...

Size dependent optical band gap of ternary I-III-VI2 semiconductor nanocrystals

Abstract: The size dependent optical band gap of the less-toxic ternary I-III-VI2 chalcopyrite-type semiconductor quantum dots (QDs), CuInS2, CuInSe2, CuGaS2, CuGaSe2, AgInSe2, AgGaS2, and AgGaSe2, were evaluated using the finite-depth-well effective mass approximation calculation. From the comparison of the calculation result with the experimental values for the CuInS2 case, it was shown that the calculation was highly valid to predict the size dependent optical gap of the ternary semiconductor QDs. The optical band gap of the above seven I-III-VI2 QDs covers a wide wavelength range from the near-infrared to ultraviolet. It has been shown that the I-III-VI2 semiconductor QDs have a significant potential as alternatives to the highly toxic cadmium-containing II-VI semiconductor QDs and they are applicable to the wide range of light emitting devices and solar cells.

A comprehensive survey of M2AX phase elastic properties

Abstract: M(2)AX phases are a family of nanolaminate, ternary alloys that are composed of slabs of transition metal carbide or nitride (M(2)X) separated by single atomic layers of a main group element. In this combination, they manifest many of the beneficial properties of both ceramic and metallic compounds, making them attractive for many technological applications. We report here the results of a large scale computational survey of the elastic properties of all 240 elemental combinations using first-principles density functional theory calculations. We found correlations revealing the governing role of the A element and its interaction with the M element on the c axis compressibility and shearability of the material. The role of the X element is relatively minor, with the strongest effect seen in the in-plane constants C(11) and C(12). We identify several elemental compositions with extremal properties such as W(2)SnC, which has by far the lowest value of C(44), suggesting potential applications as a high-temperature dry lubricant.

A novel CNTFET-based ternary logic gate design

Abstract: This paper presents a novel design of ternary logic inverters using carbon nanotube FETs (CNTFETs). Multiple-valued logic (MVL) circuits have attracted substantial interest due to the capability of increasing information content per unit area. In the past extensive design techniques for MVL circuits (especially ternary logic inverters) have been proposed for implementation in CMOS technology. In CNTFET device, the threshold voltage of the transistor can be controlled by controlling the chirality vector (i.e. the diameter); in this paper this feature is exploited to design ternary logic inverters. New designs are proposed and compared with existing CNTFET-based designs. Extensive simulation results using SPICE demonstrate that power delay product is improved by 300% comparing to the conventional ternary gate design.

Separation of Carbon Dioxide and Sulfur Dioxide Gases Using Room-Temperature Ionic Liquid [hmim][Tf2N]

Abstract: To understand capturing and/or enhanced gaseous selectivity of industrial flue gases containing CO2 and SO2 using room-temperature ionic liquids, we have developed a ternary equation of state (EOS) model for a CO2/SO2/1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([hmim][Tf2N]) system. The present model is based on a generic RK (Redlich−Kwong) EOS, with empirical binary interaction parameters of each binary system. These interaction parameters have been determined using our measured VLE (vapor−liquid-equilibrium) data for SO2/[hmim][Tf2N] and CO2/[hmim][Tf2N] and literature data for CO2/SO2. The validity of the present EOS has been checked by conducting ternary VLE experiments for the present system. With this EOS, isothermal ternary phase diagrams and solubility (VLE) behaviors have been calculated for various (T, P, and feed compositions) conditions. For large and equimolar CO2/SO2 mole ratios, the gaseous selectivity is nearly independent of the amount of the ionic liquid addition. Howe...

Iron Complexation Studies of Gallic Acid

Abstract: In this work, formation in the binary and ternary systems of the FeIII metal ion with gallic acid and glycine was investigated by means of potentiometry, conductometry, polarography, and UV−visible absorption spectroscopy techniques at 25 °C and in I = 0.10 mol·dm−3 NaNO3. The protonation equilibria of gallic acid and glycine were investigated and discussed. The acidity constants of gallic acid and glycine were determined and used for determining the stability constants of the binary and ternary complexes formed in the aqueous medium under the experimental conditions. The ternary complex formation was found to occur in a stepwise manner. The stability constants of these binary and ternary systems were calculated. The concentration distribution of the various complex species in solution was evaluated and discussed. The solid binary [FeIII−gallic acid] and ternary [FeIII−gallic acid−glycine] complexes were synthesized and characterized by elemental analysis, FT-IR, 1H NMR, and 13C NMR spectroscopy.

Phase stability of boron carbon nitride in a heterographene structure: A first-principles study

Abstract: Phase stability for monolayer boron-carbon-nitride (BNC) (l-BNC) ternary system was examined by Monte Carlo simulations and the cluster expansion technique based on first-principles calculations. All the possible atomic arrangements exhibit positive formation energies, indicating phase separation into monolayer BN and graphene. The atomic arrangements in lowest formation energy have strong preferences for B-N and C-C atoms while disfavor with B-C, C-N, B-B, and N-N bonds along the first-nearest-neighbor coordination, which have a similar tendency for cubic BNC ternary alloys predicted in our previous study. Lattice vibration significantly enhances solubility limits for l-BNC: within the framework of harmonic approximation, complete miscibility achieves at around $T=3500\text{ }\text{K}$, which is below melting lines between hexagonal BN and graphite.

Solvothermal Synthesis of V−VI Binary and Ternary Hexagonal Platelets: The Oriented Attachment Mechanism

Abstract: General synthesis of both binary and ternary V−VI based thermoelectric alloy hexagonal platelets was carried out for the first time in a unified system using a modified solvothermal method, which adopted convenient oxides as source materials and friendly ethylene glycol as both solvent and reducing agent. The structure and composition analysis reveal that the samples are pure phase with corresponding atomic ratios. Electron microscopy results indicate that the as-prepared products are uniform and highly crystallized. The formation process was studied in detail by observing time-dependent products, and it was found that the oriented attachment mechanism could be responsible for the growth of these hexagonal platelets, which exhibits intrinsic difference compared with the inferred seed-mediated growth mechanism in previous reports. The influence of pH value and polyvinyl pyrrolidone on the morphology of the products was investigated as well. This work may open up a new rationale on designing the solution sy...

Observation of a Ternary Nanocrystal Superlattice and Its Structural Characterization by Electron Tomography

Abstract: The first genuine ternary colloidal crystal (see picture) is composed of PbSe nanocrystals of two different diameters (blue and green) and of CdSe nanocrystals (red). Electron tomography shows that the superlattice is isostructural with the atomic lattice AlMgB4.

Enhanced refractometric optical sensing by using one-dimensional ternary photonic crystals

Abstract: One-dimensional ternary photonic crystals are suggested as refractometric sensing elements, for sensing very small refractive index changes of a medium. These one-dimensional ternary photonic crystals based refractometric sensing elements are not only remarkably smaller, but are also more sensitive than one-dimensional binary photonic crystal based sensing element recently suggested by researchers.

Thermodynamic modeling and optimization of the Fe–Ni–Ti system

Abstract: A thermodynamic assessment of the ternary Fe–Ni–Ti system together with a partial reassessment of the binary sub-systems Ni–Ti and Fe–Ti was made following the CALPHAD method and using the compound energy formalism (CEF). Two and four sublattices were used to model the bcc and fcc phases respectively. This allows describing the order–disorder transformations occurring not only in the ternary Fe–Ni–Ti system, but also in the quaternary Al–Fe–Ni–Ti system. The description of the C14 Laves phase TiFe2 was modified to three sublattices in order to be consistent with other Al–Fe–Ni–Ti sub-systems in which a three sublattice model is needed. Thermodynamic parameters were optimized using the available experimental data. On the basis of this optimization the stable phase diagram is calculated. Moreover stable and metastable equilibria between ordered and disordered phases based on fcc and bcc respectively are calculated.

Solution−Liquid−Solid Growth of Ternary Cu−In−Se Semiconductor Nanowires from Multiple- and Single-Source Precursors

Abstract: Ternary CuInSe2 nanowires were synthesized for the first time by the solution−liquid−solid (SLS) mechanism. Here, both metal−organic multiple- and single-source molecular precursors were thermally decomposed in the presence of molten metal nanoparticles and coordinating ligands. The nature of the precursor—multiple- compared to single-source (wherein Cu−Se−In bonds are effectively preformed)—as well as the choice of coordinating ligands, reaction temperature, and reactant order-of-addition strongly affected the morphology and composition of the reaction product obtained. Crystalline, straight, and nearly stoichiometric CuInSe2 nanowires were most readily achieved using the single-source precursor; however, careful tuning of reaction conditions could also be used to obtain high-quality nanowires from multiple-source precursor systems. The CuInSe2 nanowires are strong light absorbers from the near-infrared through the visible and ultraviolet spectral regions and, thereby, comprise new soluble and processabl...

Combinatorial Study of High Surface-Area Binary and Ternary Electrocatalysts for the Oxygen Evolution Reaction

Abstract: We present the design, fabrication, and utilization of a high-throughput combinatorial electrochemical screening platform consisting of 16 individually addressable, three-electrode chambers for rapid evaluation of supported high-surface-area nanoparticle electrocatalysts. Repeatable hydrogen adsorption/desorption surface area measurements along with oxygen evolution kinetics for carbon supported pure platinum catalysts (Pt/C) illustrate practical reproducibility ({+-}10%) across the 16 glassy carbon working electrodes. Automated liquid-precursor impregnation using robotic liquid dispensing is shown to produce catalysts in precisely controllable atomic ratios as confirmed via energy dispersive spectroscopy. The combinatorial array demonstrates the ability to produce reliable trends in electrocatalytic activity data for the oxygen evolution reaction (OER) on both binary Pt-M catalysts (with M=Ir, Re, Ru, Pd), as well as ternary Pt-Ru-M catalysts (with M=Ir, Pd), when compared to a more rigorous kinetic analysis on a rotating disk electrode. It was shown that Ru-rich materials are better suited for use as OER catalysts relative to Pt-, Ir-, Pd-, and Re-rich materials. The OER catalyst materials discovered are expected to significantly lower the necessary input power of electrochemical water splitting devices in acidic environments (proton exchange membrane fuel cell electrolyzers).

Elastic properties and electrostructural correlations in ternary scandium-based cubic inverse perovskites : A first-principles study

Abstract: Wehave performed ab initio calculations for the cubic inverse-perovskite Sc3EN(E=Al,Ga,In) systems to study their electronic band-structures and elastic properties.In this study, we used the accura ...

Density functional theory based screening of ternary alkali-transition metal borohydrides: A computational material design project

Abstract: We present a computational screening study of ternary metal borohydrides for reversible hydrogen storage based on density functional theory. We investigate the stability and decomposition of alloys containing 1 alkali metal atom, Li, Na, or K M1; and 1 alkali, alkaline earth or 3d / 4d transition metal atom M2 plus two to five BH4  groups, i.e., M1M2BH42‐5, using a number of model structures with trigonal, tetrahedral, octahedral, and free coordination of the metal borohydride complexes. Of the over 700 investigated structures, about 20 were predicted to form potentially stable alloys with promising decomposition energies. The M1Al/ Mn/ FeBH44, Li/ NaZnBH43, and Na/ KNi/ CoBH43 alloys are found to be the most promising, followed by selected M1Nb/ RhBH44 alloys. © 2009 American Institute of Physics. DOI: 10.1063/1.3148892

Influence of sputter damage on the XPS analysis of metastable nanocomposite coatings

Abstract: X-ray photoelectron spectroscopy (XPS) is a standard method of determining chemical bonding in eg nanocomposites We demonstrate that sputter-cleaning of the sample prior to analysis can substantially alter the attained information We present an in-depth analysis of sputter damage on binary and ternary TiC-based coatings in the Ti–Ni–C system XPS was performed after sputter etching with different ion energies (015–4 keV) Results are compared to data from the bulk of undamaged samples attained using high kinetic energy XPS We observe substantial sputter damage, strongly dependent on sputter energies and coating stability Metastable samples exhibit severe sputter damage after etching with 4 keV Additional samples from other Ti–Me–C (Me = Al, Fe, Cu or Pt) systems were also examined, and notable sputter damage was observed This suggests that accurate analysis of any metastable nanocomposite requires careful consideration of sputter damages