Materials Literature
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Abstract In this tutorial we review the optical and electro‐optical properties of single‐walled carbon nanotubes (CNTs). The nature of the excited states of CNTs, their production by photon and electrical excitation and their decay are analyzed. Two types of single CNT light emitters based on ambipolar e–h recombinati…
Abstract The focus of this paper is to investigate the electrical conductivity and the mechanical properties of single‐walled carbon nanotubes/polycarbonate composites. Two different direct incorporating methods were applied. In the first method PC and SWCNTs were mixed with different ratios in a small scale conical t…
Stable and monodisperse Au nanoparticles smaller than 2 nm are easily prepared by the reduction of HAuCl(4) x 4H(2)O in DMF/H(2)O in the presence of a series of bidentate ligands, 2,6-bis(1'-(n-thioalkyl)benzimidazol-2-yl)pyridine (TC(n)BIP, n = 3, 6, 8, 10, 12). The TC(n)BIP ligands afford stronger coordination abili…
The nanostructure of fiber networks of two small-molecule organogels is engineered based on a nucleation-growth fiber network formation mechanism. It is shown that the presence of a surface-active additive can improve the elasticity of the gels by enhancing branching of the fibers (see figure).
The interaction of the (110) and (111) surfaces of ceria (CeO(2)) with atomic hydrogen is studied with ab initio calculations based on density functional theory. A Hubbard U term added to the standard density functional allows to accurately describe the electronic structure of the two surfaces. The minimum energy conf…
Particle-based molecular simulations of pure diblock copolymer (DBC) systems were performed in continuum space via dissipative particle dynamics and Monte Carlo methods for a bead-spring chain model. This model consisted of chains of soft repulsive particles often used with dissipative particle dynamics. The gyroid ph…
Colloidal Co(2+):ZnSe diluted magnetic semiconductor quantum dots (DMS-QDs) were prepared by the hot injection method and studied spectroscopically. Ligand-field electronic absorption and magnetic circular dichroism (MCD) spectra confirm homogeneous substitutional speciation of Co(2+) in the ZnSe QDs. Absorption spect…
Mesogenic scaffoldings are constructed from highly luminescent 4,4-difluoro-4-bora-3a,4a-diaza- s -indacene (Bodipy) linked via an amide or an ethynyl spacer to a functional amphipathic platform. A single-crystal X-ray structure of a parent methoxy compound revealed that the Bodipy fragment is almost perpendicular to…
The reaction of phenylphosphonic acid (PhPO(3)H(2)) with the mixed-valent basic oxo-centered manganese triangle [Mn(3)O(O(2)CCMe(3))(6)(py)(3)] (1; where py=pyridine) in the presence of a suitable base gives four different manganese clusters depending on the identity of the base. The syntheses and structural character…
Optical Bragg reflections and small-angle X-ray scattering (see figure) reveal that dispersions of Goethite (FeOOH) nanorods spontaneously form layered (smectic A) structures, although their 55 % length polydispersity exceeds the theoretical limit by a factor of three. Here, sedimentation and size partitioning contrib…
Using 3D k.p calculation including strain and piezoelectricity we predict variation of electronic and optical properties of InAs/GaAs quantum dots (QDs) with the substrate orientation. The QD transition energies are obtained for high index substrates [11k], where k = 1,2,3 and are compared with [001]. We find that the…
We establish relations between the statistics of g factors and the fluctuations of energy in metallic nanoparticles where spin-orbit coupling is present. These relations assume that the electron dynamics in the grain is chaotic. The expressions we provide connect the second moment of the g factor to the root-mean squa…
The excitation-chain theory of the glass transition, proposed in an earlier publication, predicts diverging, super-Arrhenius relaxation times and, via a similarly diverging length scale, suggests a way of understanding the relations between dynamic and thermodynamic properties of glass-forming liquids. I argue here th…
The time-convolutionless master equation for the electronic populations is derived for a generic electron-phonon Hamiltonian. The equation can be used in the regimes where the golden rule approach is not applicable. The equation is applied to study the electronic relaxation in several models with the finite number of…
By employing the analytic embedded-atom potentials of Mei {\it et al.} [Phys. Rev. B 43, 4653 (1991)] we have calculated the phonon dispersion spectra for six fcc metals: Cu, Ag, Au, Ni, Pd and Pt. We have also investigated thermal properties of these metals within the quasiharmonic approximation. Results for the latt…
In this review, we hope to give the reader a self-contained contemporary presentation of the application of Landau theory to ferroelectrics. We begin by developing Landau theory for homogenous bulk ferroelectrics and then consider the finite-size (thin film) case within the related Landau-Ginzburg approach. Next we di…
We address the quality of electrical contact between carbon nanotubes and metallic electrodes by performing first-principles calculations for the electron transmission through ideal 2- and 3-terminal junctions, thus revealing the physical limit of tube-metal conduction. The structural model constructed involves surrou…
A hybrid white-light-emitting device (see figure) whose emission originates only from ternary nanocrystal (quantum dot) composites but whose luminance performance matches the requirements of the lighting industry is demonstrated. The bright white-light emission is obtained by controlling the Förster energy transfer an…
Nacre is a natural nanocomposite material with superior mechanical strength and toughness. What roles do the nanoscale structures play in the inelasticity and toughening of nacre? Can we learn from this to produce nacre-like nanocomposites? Here we report in situ dynamic atomic force microscope observations of nacre w…
An investigation is reported on the interfacial properties of nanometric colloidal silica dispersions in the presence of a cationic surfactant. These properties are the result of different phenomena such as the particle attachment at the interface and the surfactant adsorption at the liquid and at the particle interfa…