Materials Literature
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Monodisperse nanospheres are formed by coordination polymerization tetrakis(4-pyridyl)porphyrin-metal complexes with chloroplatinic acid in aqueous solution. The porphyrin nanospheres and their platinized nanocomposites have potential applications in catalysis and solar energy conversion systems.
We report the controllable resistance of multiwalled carbon nanotube bundles for the possible application in nanoscale electronics. The resistance as well as the variation of resistance with temperature depends on the bundle diameter. The larger the diameter, smaller is the resistance and weaker is the variation of re…
Utilizing first-principles computational techniques, we have mapped out structural instabilities in the Ruddlesden-Popper homologous oxide superlattice families with a general chemical formula ${A}_{n\ensuremath{-}1}{A}_{2}^{\ensuremath{'}}{\text{Ti}}_{n}{\text{O}}_{3n+1}$, $A=\text{Sr}$, Ba, and Pb (perovskite-type s…
Polymer bottlebrushes with monodisperse oligoproline side chains were efficiently synthesized, and the conformation of the peptide side chains in different solvents was investigated. Polymers with number-average degrees of polymerization (DPn) of 89 and 366 were obtained by polymerization of the macromonomer in iPrOH/…
We report on very effective stabilization of porous silicon optical devices through a chemical surface modification technique. Such a chemical treatment proves to alter the growth of native silicon oxide on pore surfaces and thus prevents the optical device from chemical aging. As an example, we apply this technique t…
The adsorption of water on perfect TiO(2)(110) surface is studied by quantum molecular dynamics simulation adopting a periodic model formed by five water molecules on a (5 x 1) surface unit cell of a five layer slab of TiO(2). The total simulation time is 3.2 ps. At about 1.3 ps, one water molecule dissociates with th…
We present a theoretical model to study the effect of microwave radiation on Weiss oscillations. In our proposal Weiss oscillations, produced by a spatial periodic potential, are modulated by microwave radiation due to an interference effect between both, space and time-dependent, potentials. The final magnetoresistan…
A surface-enhanced Raman scattering fiber sensor with chessboard nanostructure on a cleaved fiber facet is studied by finite-difference time-domain method. Surface plasmons at the metal coated nanostructured fiber facet can be effectively excited and strong local electric field enhancement is obtained. Studies on the…
Abstract Neutral hydrolytic depolymerization of PET (Polyethylene terephthalate) waste was studied using 0.5‐L high pressure autoclave at the temperatures 100, 150, 200, 230, and 250°C at autogenious pressures 15, 80, 230, and 451 psi (pound per square inch) and time intervals of 60, 90, 120, and 150 min, respectively…
A novel mechanism based on aliovalent doping, allowing fine tuning of the nanostructure and surface topography of solution-derived ceria films, is reported. While under reducing atmospheric conditions, non-doped ceria films are inherently polycrystalline due to an interstitial amorphous Ce(2)C(3) phase that inhibits g…
By ab initio molecular dynamics simulations, we unraveled the unique network structure of amorphous Ge1Sb2Te4, which shows high rank of ordering and mostly consists of distorted defective octahedrons with a small portion of distorted tetrahedrons. The phase transition from amorphous to cubic Ge1Sb2Te4 would be mainly…
Position- and density-controlled ZnO nanorod arrays (ZNAs) were successfully grown on a Si substrate through a low temperature (90 °C) hydrothermal approach assisted by pre-formed ZnO micro/nanodots. The ZnO dots on Si substrates were prepared by a spin-coating technique, through which the pattern and density of the d…
Licht am Ende des Tunnels: Zwei Arten eindimensionaler Mikrostrukturen, Röhren und Stäbe, wurden aus 9,10-Bis(phenylethinyl)anthracen hergestellt. Beide Mikrostrukturen absorbieren Anregungslicht und tragen die Photolumineszenz(PL)-Emission an die Spitzen weiter, doch die Luft im Innern der hohlen Röhren verändert das…
One-dimensional Eu(3+) doped gadolinium oxysulfide (Gd(2)O(2)S:Eu(3+)) nanotubes/nanorods have been synthesized via precursors of Gd(OH)(3) nanostructures using a hydrothermal technique. The blue-shifts in the optical spectra for the Gd(2)O(2)S:Eu(3+) system corresponding to the fundamental absorption and Eu(3+)-X(2-)…
The semiconductor-metal transition of vanadium dioxide (VO2) thin films epitaxially grown on C-plane sapphire is studied by depositing Au nanoparticles onto the thermochromic films forming a metal-semiconductor contact, namely, a nano-Au-VO2 junction. It reveals that Au nanoparticles have a marked effect on the reduct…
We report the clearly observed tunneling magnetoresistance at 5 K in magnetic tunnel junctions with Co-doped ZnO as a bottom ferromagnetic electrode and Co as a top ferromagnetic electrode prepared by pulsed laser deposition. Spin-polarized electrons were injected from Co-doped ZnO to the crystallized Al2O3 and tunnel…
The physics of deep defect states associated with group-III (Ga, In, Tl) impurities in PbTe has been of great interest over the last several decades. Three different models have been proposed to understand interesting and unusual properties exhibited by these impurities. These are ``impurity level'' model, ``mixed-val…
Understanding the loss of ferroelectricity in submicron- and nano-sized perovskites is an issue that has been debated for decades. Here we report results from a high-energy x-ray diffraction (XRD) study on a prime example of the perovskite's family, ${\text{BaTiO}}_{3}$ ceramics with a grain size ranging from 1200 to…
We derive and analyze the $f$-sum rule for a two-dimensional system of interacting electrons whose behavior is described by the Dirac equation. We apply the sum rule to analyze the spectral weight transfer in graphene within different approximations discussed in the literature. We find that the sum rule is generically…
In recent works, we have suggested that plasmonic covers may provide an interesting cloaking effect, dramatically reducing the overall visibility and scattering of a given object. While materials with the required properties may be directly available in nature at some specific infrared or optical frequencies, this is…