Materials Literature
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High-quality (uniform in size and morphology (σ = 3−5%), high crystallinity, high QY (40−85%), sharp and narrow absorption onsets and PL peaks (fwhm = 27−33 nm)) violet- to red-emitting ZnSe/CdSe core/shell nanocrystals have been prepared by the deposition of Cd/Se precursors (CdO and elemental Se, respectively) into…
The hydrogen adsorption sites in MOF5 were determined using neutron powder diffraction along with first-principles calculations. The metal-oxide cluster is primarily responsible for the adsorption while the organic linker plays only a secondary role. Equally important, at low temperatures and high-concentration, H2 mo…
A simple method is developed to synthesize gram quantities of uniform Ge nanowires (GeNWs) by chemical vapor deposition on preformed, monodispersed seed-particles loaded onto high surface area silica support. Various chemical functionalization schemes are investigated to passivate the GeNW surfaces using alkanethiols…
The surfaces of TiO2 nanocrystals were modified with amorphous aluminum-oxide layers using a surface sol-gel process to control the interaction between supports and metal particles. Ultrastable Au nanocatalysts were prepared by the deposition of Au nanoparticles on the surface-modified TiO2 nanocrystals using a deposi…
The dispersibility and bundle defoliation of single-walled carbon nanotubes (SWNTs) of small diameter (<1 nm) have been evaluated on CoMoCAT samples with narrow distribution of diameters. As previously observed by photoluminescence and Raman spectroscopy, the CoMoCAT sample exhibits a uniquely narrow distribution of (…
The adsorption of As and Se from dilute aqueous solutions, representing model power-plant effluent streams, by calcined and uncalcined layered double hydroxide (LDH) adsorbents has been investigated. The results indicate that As(V) has a greater adsorption capacity than Se(IV) for both calcined and uncalcined LDHs. An…
A simple and easy method to prepare super-liquid-repellent surfaces is proposed. Sol-gel films were prepared by hydrolysis and condensation of alkoxysilane compounds. Both surface energy and roughness were controlled using colloidal silica particles and fluoroalkylsilane. When the fractional amounts of both colloidal…
One-dimensional supramolecular aggregates can form networks at exceedingly low concentrations. Recent experiments in several laboratories, including our own, have demonstrated the formation of gels by these systems at concentrations well under 1% by weight. The systems of interest in our laboratory form either cylindr…
We present an ab initio dynamics investigation within a density-functional perturbation theory framework of the properties of the conjugated polymer poly-para-phenylene vinylene (PPV) in both the isolated chain and crystalline states. The calculated results show that for an isolated chain, most of the vibrational mode…
We have computed the conductance of a side-contacted metallic carbon nanotube(CNT) with one end dangling outside a probe by using a tight-binding model. We have also demonstrated that the average conductance of a CNT with a finite dangling end is about twice as that of CNT with an infinite dangling end. When the conta…
Mechanisms for carrier generation in zinc antimonate (ZnSb 2 O 6 ) with a wide band gap were examined in relation to its crystallinity. ZnSb 2 O 6 prepared by the reaction of Sb 2 O 5 sol and 3ZnCO 3 ·4Zn(OH) 2 was sintered at 893, 1173, and 1393 K, and characterized by X‐ray diffraction (XRD), electrical conductivity…
Here we report the formation and spectroscopic properties of cadmium sulfide (CdS) nanocrystal systems: individual nanocrystal and CdS aggregates. The optical absorption and luminescence spectra of the aggregated CdS nanocrystals and individual nanocrystal show exciton aggregate and individual exciton characteristics.…
The thermal stability of ultrasmall $0.4\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ single-walled carbon nanotubes (SWNTs) are studied by means of Raman-scattering measurements under a vacuum. The $0.4\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ SWNTs are very stable when they are confined inside the channels of the $\mathrm{A…
Abstract Cyclohexanone–formaldehyde resins were modified in situ with α,ω‐diamine polydimethylsiloxanes and α,ω‐dihydroxy polydimethylsiloxanes. Melting points, solubilities in organic solvents, gel permeation chromatographs, Fourier transform infrared spectra, and NMR spectra of the modified resin were determined, an…
The thermodynamic conductivity data ${\ensuremath{\sigma}}_{\mathrm{ac}}(f,T)$ of the acceptor $({\mathrm{Ca}}^{2+})$-doped $\mathrm{Sr}{\mathrm{Bi}}_{2}{\mathrm{Ta}}_{2}{\mathrm{O}}_{9}$, a fatigue-free ferroelectric, was subjected to a modified Jonscher's power law ${\ensuremath{\sigma}}^{\ensuremath{'}}(f)={\ensure…
A versatile synthetic approach to cadmium chalcogenide nanoparticles in the mesopores of SBA-15 silica as a host matrix was developed. The use of cadmium organochalcogenolates of the type Cd(XPh)(2).TMEDA (X = S, Se, Te) allowed the preparation of nanoparticles of all three cadmium chalcogenides following the same exp…
The optical properties of sol-gel synthesized porous silica excited by synchrotron radiation in the 4-10 eV range of samples with different porosity at 8 K and room temperature are reported. The analysis of the ultraviolet photoluminescence indicate the contributions of two different emitting centers. The spectral and…
We study the aging of a colloidal laponite glass by measuring the dynamic structure factor of dilute embedded tracer particles on micrometric length scales. We show that an initial aging regime, where the decay time grows exponentially with aging time t(w), tau approximately exp (gamma t(w)), is followed by a full agi…
We have fabricated (La,Sr)MnO3 (LSMO)-based magnetic tunnel junctions with Ru-doped LSMO (LSMRO) film used as one of the electrodes. The Ru doping enhances the coercivity of LSMO, resulting in a sharp steplike tunnel magnetoresistance (TMR) response with a high contrast in the coercive field (Hc) for magnetization rev…
Ring sulfonation of a poly(thienothiophene) produces a stable, low‐bandgap (< 1.2 eV), water‐processable, intrinsically conductive polymer. The optical properties of the polymer can be easily modified by varying the sulfonation level and optical‐bandgap tuning can also be achieved through the use of a polycation. W…