Materials Literature
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A modified polyol process has been used to synthesize intermetallic nanocrystals and nanowire networks directly in solution using a one-pot reaction. The synthesis of AuCu nanocrystals in tetraethylene glycol shows that atomically ordered intermetallic nanocrystals form above 250 °C, while atomically disordered alloy…
Electron- and hole-transfer reactions are studied in colloidal InP quantum dots (QDs). Photoluminescence quenching and time-resolved transient absorption (TA) measurements are utilized to examine hole transfer from photoexcited InP QDs to the hole acceptor N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD) and electron t…
Single-stranded DNA wrap helically around individual single-walled carbon nanotubes to form DNA/CNT hybrids, which are both stable and dispersible in aqueous solution. Subjected to ion-exchange chromatography, a hybrid elutes at an ionic strength that depends on the electronic character and diameter of the core nanotu…
Structural, optical, and field-emission properties of ZnO nanowire arrays grown at 90°C are investigated. Single-crystalline ZnO nanowires with low level of oxygen vacancies are obtained at low temperatures. The nanowire growth is strongly dependent on the seeding method used but independent of the substrate materials…
We report on a Ni ${L}_{2,3}$ edge x-ray absorption spectroscopy study in $R\mathrm{Ni}{\mathrm{O}}_{3}$ perovskites. These compounds exhibit a metal-to-insulator (MI) transition as temperature decreases. The ${L}_{3}$ edge presents a clear splitting in the insulating state, associated to a less hybridized ground stat…
In order to explain recent experiments reporting a motion of magnetic domain walls (DW) in nanowires carrying a current, we propose a modification of the spin transfer torque term in the Landau-Lifchitz-Gilbert equation. We show that it explains, with reasonable parameters, the measured DW velocities as well as the va…
Ti-substituted perovskites ${\mathrm{La}}_{0.7}{\mathrm{Sr}}_{0.3}{\mathrm{Mn}}_{1\ensuremath{-}x}{\mathrm{Ti}}_{x}{\mathrm{O}}_{3}$ with $0\ensuremath{\leqslant}x\ensuremath{\leqslant}0.20$, were investigated by neutron diffraction, magnetization, electric resistivity, and magnetoresistance (MR) measurements. All sam…
A numerical method for computation of heteroepitaxial growth in the presence of strain is presented. The model used is based on a solid-on-solid model with a cubic lattice. Elastic effects are incorporated using a ball and spring type model. The growing film is evolved using Kinetic Monte Carlo (KMC) and it is assumed…
The $c(2\ifmmode\times\else\texttimes\fi{}2)$ reconstruction of $(001)\phantom{\rule{0.2em}{0ex}}{\mathrm{PbTiO}}_{3}$ surfaces is studied by means of first principles calculations for paraelectric (nonpolar) and ferroelectric (in-plane [100] polarized) films. Analysis of the atomic displacements in the near-surface r…
Gold catalysts supported on cerium oxide were prepared by solvated metal atom dispersion (SMAD), by deposition-precipitation (DP), and by coprecipitation (CP) methods and were characterized by X-ray diffraction (XRD), temperature programmed reduction (TPR), and X-ray photoelectron spectroscopy (XPS). The catalytic act…
We experimentally demonstrate the first midinfrared (mid-IR) resonant magnetic nanostructures exhibiting a strong magnetic response corresponding to a negative permeability. This result is an important step toward the achievement of a negative refractive index in the IR. The possibility of extending negative permeabil…
Lanthanide oxides as sources of lanthanides provided 3D coordination polymers under hydrothermal conditions in which distinct [Ln14(μ6-O)(μ3-OH)20(H2O)8]20+ (Ln=Y, Gd, Dy) clusters are linked to two different types of copper centers through isonicotinate ligands. The unprecedented 3D network topology of these isostruc…
We explored using a magnetic field to modulate the permeability of polyelectrolyte microcapsules prepared by layer-by-layer self-assembly. Ferromagnetic gold-coated cobalt (Co@Au) nanoparticles (3 nm diameter) were embedded inside the capsule walls. The final 5 mum diameter microcapsules had wall structures consisting…
We report the preparation and characterization of light-responsive delivery vehicles, microcapsules composed of multiple polyelectrolyte layers and light-absorbing gold nanoparticles. The nanostructured capsules were loaded with macromolecules (fluorescein isothiocyanate-labeled dextran) by exploiting the pH-dependenc…
Periodic mesoporous organosilicas (PMOs) represent an exciting new class of organic-inorganic nanocomposites targeted for a broad range of applications such as catalysis and sensing, separations, and microelectronics. Their hallmark is the presence of organic bridging groups incorporated into the channel walls of an o…
Ligand exchange reactions of 1.5-nm triphenylphosphine-stabilized nanoparticles with omega-functionalized thiols provides a versatile approach to functionalized, 1.5-nm gold nanoparticles from a single precursor. We describe the broad scope of this method and the first mechanistic investigation of thiol-for-phosphine…
Colloidal quantum dots are semiconductor nanocrystals well dispersed in a solvent. The optical properties of quantum dots, in particular the wavelength of their fluorescence, depend strongly on their size. Because of their reduced tendency to photobleach, colloidal quantum dots are interesting fluorescence probes for…
The ground-state structural and electronic properties of ferroelectric $\mathrm{Bi}\mathrm{Fe}{\mathrm{O}}_{3}$ are calculated using density functional theory within the local spin-density approximation (LSDA) and the $\mathrm{LSDA}+U$ method. The crystal structure is computed to be rhombohedral with space group $R3c$…
Hydrogen loading in $\mathrm{X}∕\mathrm{V}(\mathrm{X}=\mathrm{Cr},\mathrm{Mo},\mathrm{Fe})$ supercells as a function of the $\mathrm{H}$ position within the supercell was studied. Preferred $\mathrm{H}$ position is governed by the energy cost of the accompanying volume expansion, which is proportional to the correspon…
Abstract Summary: The phase behavior and optical properties of a cholesteric ternary copolymer, containing nematogenic phenylbenzoate, cholesteric, and photochromic diarylethene side groups, and its mixture with 2 wt.‐% fluorescent dopant were studied. The investigation of the kinetics of a photochemical opening‐cycle…