Materials Literature
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Nanocrystalline silicon carbide films were deposited by thermal plasma chemical vapor deposition, with film growth rates on the order of 10μm∕min. Films were deposited on molybdenum substrates, with substrate temperature ranging from 750-1250 °C. The films are composed primarily of β-SiC nanocrystallites. Film mechani…
We investigate the element- and size-dependent electron stability of ${\mathrm{Au}}_{n}{M}^{+}$ clusters ($M=\mathrm{Sc}$, Ti, V, Cr, Mn, Fe, Au; $n\ensuremath{\leqslant}9$) by means of first-principles density functional calculations. The interplay between the cluster atomic arrangements and their electronic and magn…
Full of air: Electrostatic layer-by-layer assembly of polyelectrolyte multilayers was successfully accomplished on the surface of an air microbubble (core). The resulting polyelectrolyte shell stabilizes the air microbubbles against collapse and prevents the dissolution of air in aqueous media. Air-containing polyally…
Cooperation of mother and daughter vesicles, which are self-assembled from an ill-defined hyperbranched copolymer, leads to fission of the daughter membrane in a cytomimetic process (see picture; red: mother vesicle, green: daughter vesicle). This is the first example of giant polymer vesicles (5–200 μm) being used as…
Biomimetic light-harvesting antennae are made available by noncovalent polymerization of semisynthetic zinc chlorins. The excellent solubility and the prolonged stability of the zinc chlorin aggregates enables spectroscopic investigation of their reversible formation (see picture). The rod-shaped structure of these ag…
A demand currently exists for a method of assessing the purity of single-wall carbon nanotubes (SWNTs), which will allow for meaningful material comparisons. An established metric and protocol will enable accurate and reproducible purity claims to be substantiated. In the present work, the ability to accurately quanti…
Theoretical investigations of the electronic, magnetic and structural properties of LaTiO 3 and YTiO 3 have been made. In the framework of GGA and GGA+U scheme we analyzed the effect of the local Coulomb interaction ( U ) value on the atomic forces acting in the experimental structure. The optimal parameters of the el…
We report results of low-temperature thermodynamic and transport measurements of Pb1-xTlxTe single crystals for Tl concentrations up to the solubility limit of approximately x=1.5%. For all doped samples, we observe a low-temperature resistivity upturn that scales in magnitude with the Tl concentration. The temperatur…
Crystallization at production scale is typically a poorly understood unit operation, with little implementation of the first principles aspect of crystallization in its design, optimization, and control. Problems with production crystallizers include the following: (1) inconsistencies of batch-to-batch in terms of the…
Polymeric methyltrioxorhenium (poly-MTO) is the first member of a new class of organometallic hybrids which adopts the structural motives and physical properties of classical perowskites in two dimensions. In this study we demonstrate how the electronic structure of poly-MTO can be tailored by intercalation of organic…
While isovalent doping of GaAs (e.g., by In) leads to a repulsion between the solute atoms, two Cr, Mn, or Fe atoms in GaAs are found to have lower energy than the well-separated pair, and hence attract each other. The strong bonding interaction between levels with t2 symmetry on the transition metal (TM) atoms result…
We present atomic-scale computer simulations in equiatomic L1$_0$-CoPt where Molecular Dynamics and Monte Carlo techniques have both been applied to study the vacancy-atom exchange and kinetics relaxation. The atomic potential is determined using a Tight-Binding formalism within the Second-Moment Approximation. It is…
We study spin transport in forward and reverse biased junctions between a ferromagnetic metal and a degenerate semiconductor with a delta-doped layer near the interface at relatively low temperatures. We show that spin polarization of electrons in the semiconductor, Pn, near the interface increases both with the forwa…
Quantum chemical calculations including embedding, scalar relativistic, and dynamic electron correlation effects on Cs2NaYCl6:(CeCl6)3- embedded clusters predict: (i) red shifts of the 4f->5d(t2g) transition with pressure and (ii) bond length shortening upon 4f->5d(t2g) excitation. Both effects are found to be connect…
Optical properties of nanocrystalline red-emitting phosphor, europium-doped yttria (Y2O3:Eu3+), of average particle size of 15nm are investigated. The intensity of the strongest emission line at 612nm is found to be highest in the nanocrystalline sample with 4at.wt% of europium. The narrow electronic emission spectrum…
There are many methods for analyzing solid-state kinetic data. They are generally grouped into two categories, model-fitting and isoconversional (model-free) methods. Historically, model-fitting methods were widely used because of their ability to directly determine the kinetic triplet (i.e., frequency factor [A], act…
We have identified, for the first time, the change in symmetry at the ferroelectric transition TFE near 1023K of the ferroelectromagnet YMnO3. This transition takes place 300K below the transition to the centrosymmetric state at TIP. Single crystal synchrotron diffraction coupled to a group theoretical analysis show t…
Large-scale alignment of lamellae in thin films of diblock copolymers containing polyacrylonitrile and poly(n-butyl acrylate) was achieved by casting copolymer solution on a silicon substrate moved away at a constant speed from the casting nozzle (zone-casting). Grazing incidence small-angle X-ray scattering revealed…
One ligand, five NIR-emitting complexes: Tropolonate (trp) ligands sensitize the near-infrared emission of several lanthanide (LnIII) ions upon formation of [Ln(trp)4]− complexes (Ln=Nd, Ho, Er, Tm, and Yb; see emission spectra). The solid-state structures and solution-state photophysical properties of the [Ln(trp)4]−…
Crystallization of the thermodynamically metastable β glycine is explained on the basis of its growth at the opposite poles of the crystal (see graph) and by considering the structure of the relevant surfaces of the three polymorphs and their interactions with solvent molecules.