Materials Literature
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Enhanced photoluminescence (PL) is reported from Mn2+-doped CdS nanocrystals capped with ZnS (CdS:Mn/ZnS core/shell) that were prepared using a reverse micelle route. Compared to organically (n-dodecanethiol) capped CdS:Mn nanocrystals, CdS:Mn/ZnS core/shell nanocrystals exhibited much stronger and sharper Mn2+ 4T1–6A…
A new coordination-polymer-precursor route has been developed to synthesize nanowires under hydrothermal conditions. In the present work, well-aligned gamma-MnO(2) nanowires, growing along the [0 0 2] axis, have successfully been prepared by selecting an appropriate coordination polymer [[Mn(SO(4))(4,4'-bpy)(H(2)O)(2)…
A route for producing semiconducting polymer blends is demonstrated in which a doped pi-conjugated polymer is forced into a three-dimensionally continuous minor phase by the self-assembly of colloidal particles and block copolymers. The resulting cellular morphology can be viewed as a high-internal phase polymeric emu…
Excitation energies for wurtzite spherical ZnS and CdSe quantum dots in the range of 40–4000 atoms were calculated using empirical pseudopotentials and a real-space basis. The energies are compared to experiments and other pseudopotential models. For ZnS quantum dots, squared transition dipole sums were computed effic…
We report local-density-functional results that show that narrow nanotubes with optimized diameters between about 0.34 and 0.5 nm can be either semiconducting or metallic, but with electron structures near the Fermi level that often cannot be understood starting from the graphene sheet model, successful in the study o…
Abstract In this work, halogen‐free, flame‐retarded polyethylene was investigated to study the effect of inorganic fillers on the improvement of flame retardancy and the suppression of smoke density. Through analyses on the thermal stability and smoke density, it was found that the flame retardancy developed by magnes…
Single crystals of Nd0.5Ca0.5MnO3 and Pr0.6Ca0.4MnO3 show current-induced insulator-metal transitions at low temperatures. In addition, the charge-ordering transition temperature decreases with increasing current. The electroresistive ratio, defined as r0.5/rI where r0.5 is the resistivity at a current of 0.5 mA and r…
This paper proposes a new volume function for calculation of the entropy of planar granular assemblies. This function is extracted from the antisymmetric part of a new geometric tensor and is rigorously additive when summed over grains. It leads to the identification of a conveniently small phase space. The utility of…
Dielectric relaxation spectroscopy (10−1 Hz to 106 Hz) is employed to study the molecular dynamics of poly(dimethylsiloxane) (PDMS, Mw=1.7×105 g mol−1 and Mw=9.6×104 g mol−1) as grafted films with thicknesses d below and above the radius of gyration Rg. For the thinnest films the molecular dynamics becomes faster by u…
Elegant three-dimensional MoS2 nanoflowers were uniformly formed via heating a MoO2 thin film in a vapor sulfur atmosphere. Tens to hundreds of petals were self-assembled within a single nanoflower. Each petal, 100–300 nm wide and only several nanometers thick, exhibited a hexagonal structure. The number of petal laye…
We propose that the indirect adatom-adatom interaction mediated by the conduction electrons of a metallic surface is responsible for the $\sqrt{3}\times \sqrt{3}\Leftrightarrow 3\times 3$ structural phase transitions observed in Sn/Ge (111) and Pb/Ge (111). When the indirect interaction overwhelms the local stress fie…
There are two competing views of itinerant ferromagnetism, the first viewing ferromagnetism as resulting from the indirect coupling between local moments via the itinerant carrier dynamics, the so-called RKKY mechanism, while in the alternative picture, ferromagnetism results from the spin polarization of itinerant ca…
The morphology of the microcrystalline zinc oxide formed by reaction of zinc salts with sodium hydroxide depends critically on the reaction conditions. To understand this, the nature of the solid product has been probed by scanning electron microcopy (SEM) and X-ray diffraction (XRD) and the concentration of zinc rema…
We have developed a simple, efficient process for solubilization of single-wall carbon nanotubes (SWNTs) with amylose in aqueous DMSO. This process requires two important conditions, presonication of SWNTs and subsequent amylose treatment in an optimum mixture of DMSO/H2O. The former step separates SWNT bundles, and t…
We report on the development of a dilute suspension of ferroelectric particles in a nematic liquid-crystal (LC) host. We found that the submicron particles do not disturb the LC alignment and the suspension macroscopically appears similar to a pure LC with no readily apparent evidence of dissolved particles. The suspe…
Methods have been used to generate air bubbles beneath a planar air−water interface, stabilized by partially hydrophobic quasi-spherical silica particles (primary diameter of 20 nm) in pure water. Particles tended to aggregate at the planar interface, and all the silica dispersions had low foamability. However, those…
We report systematic first-principles calculations for ordered zinc-blende compounds of the transition metal elements V, Cr, and Mn with the $\mathrm{sp}$ elements N, P, As, Sb, S, Se, and Te, motivated by a recent fabrication of zinc-blende CrAs, CrSb, and MnAs. They show a ferromagnetic half-metallic behavior for a…
Colloidal CdTe quantum dots prepared in TOP/DDA (trioctylphosphine/dodecylamine) are transferred into water by the use of amino−ethanethiol•HCl (AET) or mercaptopropionic acid (MPA). This results in an increase in the photoluminescence quantum efficiency and a longer exciton lifetime. For the first time, water-soluble…
Single crystals of (Ca2CoO3)0.7CoO2 were grown using a modified strontium chloride flux technique, and their electrical and thermal properties were determined. Growth conditions were established for obtaining plate-like single crystals of a relatively large size (5×10×0.05 mm3). At 973 K, thermoelectric power S and el…
The itinerant-electron metamagnetic (IEM) transition and magnetocaloric effects (MCE's) in the $\mathrm{La}({\mathrm{Fe}}_{x}{\mathrm{Si}}_{1\ensuremath{-}x}{)}_{13}$ and $\mathrm{La}({\mathrm{Fe}}_{x}{\mathrm{Si}}_{1\ensuremath{-}x}{)}_{13}{\mathrm{H}}_{y}$ compounds have been investigated. The $\mathrm{La}({\mathrm{…