Materials Literature
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We describe a swelling-based method to prepare sterically stabilized polymer colloids with different functional groups or biomolecules attached to their surface. It should be applicable to a variety of polymeric colloids, including magnetic particles, fluorescent particles, polystyrene particles, PMMA particles, and s…
Molybdenum disulfide nanowires and nanoribbons have been synthesized by a two-step, electrochemical/chemical synthetic method. In the first step, MoO(x) wires (a mixture of MoO(2) and MoO(3)) were electrodeposited size-selectively by electrochemical step-edge decoration on a highly oriented pyrolytic graphite (HOPG) s…
Theoretical methods based on density functional theory have been employed to search for Prussian blue analogues with Curie temperatures higher than the ones reached today. Our study suggests several possible cyano-bridged compounds as candidates to present stronger exchange coupling and higher ordering temperatures th…
We report here the first example of peptide-functionalized gold nanoparticles hydrolytically active against carboxylate esters. The active units are constituted by His-Phe-OH terminating thiols. The confinement of the catalytic units in the monolayer covering the nanoparticles triggers a cooperative hydrolytic mechani…
In a recent Letter the phase diagram of Co/Cu/Ni/Cu(100) and Co/Fe/Ni/Cu(100) trilayers was determined experimentally as well as theoretically. Whereas we do not object the presented results, we remark that published work was not commented on. Especially, much more information can be extracted out of the measurements…
The temperature dependence of the band gap of semiconducting single-wall carbon nanotubes (SWNTs) is calculated by direct evaluation of electron-phonon couplings within a "frozen-phonon" scheme. An interesting diameter and chirality dependence of E(g)(T) is obtained, including nonmonotonic behavior for certain tubes a…
We present experiments on the dynamic buckling and fragmentation of slender rods axially impacted by a projectile. By combining the results of Saint-Venant and elastic beam theory, we derive a preferred wavelength lambda for the buckling instability, and experimentally verify the resulting scaling law for a range of m…
We have studied the transient evolution of electrons distributed over two levels in a wide quantum well, with the two levels below the optical phonon energy, after an ultrafast interband excitation and cascade emission of optical phonons. If electrons are distributed near the top of the passive region, a temporal nega…
We present small-angle neutron scattering data proving that, on the insulating side of the metal-insulator transition, the doped perovskite cobaltite La(1-x)Sr(x)CoO(3) phase separates into ferromagnetic metallic clusters embedded in a nonferromagnetic matrix. This induces a hysteretic magnetoresistance, with temperat…
An environmentally harmless method of synthesizing extremely small CdSe and highly luminescent CdSe/CdS core–shell quantum dots (see Figure) with CdSe cores of 1.2–1.5 nm diameter is reported. The CdSe/CdS core–shell quantum dots exhibit 60–80 % quantum yield at room temperature. The emission peak is tunable from 445…
Landauer's formula relates the conductance of a quantum wire or interface to transmission probabilities. Total transmission probabilities are frequently calculated using Green function techniques and an expression first derived by Caroli. Alternatively, partial transmission probabilities can be calculated from the sca…
Time-dependent density functional theory (TDDFT) is presently enjoying enormous popularity in quantum chemistry, as a useful tool for extracting electronic excited state energies. This article discusses how TDDFT is much broader in scope, and yields predictions for many more properties. We discuss some of the challeng…
We grew ${\mathrm{S}\mathrm{r}\mathrm{T}\mathrm{i}\mathrm{O}}_{3}$ on ${\mathrm{S}\mathrm{r}\mathrm{T}\mathrm{i}\mathrm{O}}_{3}(001)$ by pulsed laser deposition, while observing x-ray diffraction at the $(00\frac{1}{2})$ position. The drop $\ensuremath{\Delta}I$ in the x-ray intensity following a laser pulse contains…
The iron(III)-substituted tungstogermanate [Fe6(OH)3(A-alpha-GeWO34(OH)3)2]11- (1) has been synthesized and characterized by IR, elemental analysis, SQUID magnetometry, electron paramagnetic resonance (EPR), and electrochemistry. Single-crystal X-ray analysis was carried out on Cs4Na7[Fe6(OH)3(A-alpha-GeW9O34(OH)3)2]…
CdTe quantum dots show increased quantum yields when incorporated into a temperature-sensitive poly(N-isopropylacrylamide) hydrogel (see Figure). The fluorescence intensities and maximum emission wavelengths are sensitive to external temperature stimuli and are completely reversible.
An ultrafast electrochromic display is fabricated based upon well defined nanotube arrays of poly(3,4-ethylenedioxythiophene), PEDOT (see Figure). The thin nature of the nanotube walls (10 – 20 nm) offers a short ion-diffusion distance, which results in an ultrafast switching rate (color-switching time < 10 ms). The a…
ZnO nanowires doped with a high concentration Ga, In, and Sn were synthesized via thermal evaporation. The doping content defined as X/(Zn + X) atomic ratio, where X is the doped element, is about 15% for all nanowires. The nanowires consist of single-crystalline wurtzite ZnO crystal, and the average diameter is 80 nm…
Nanoparticles strung on nanotubes, like a beaded necklace (see Figure), have been synthesized by a simple low temperature supercritical solution method. That the crystalline spherical Co3O4 nanoparticles on multiwalled carbon nanotubes are a step towards high-density integrated nanometer-scale functional devices is de…
Microspheres of wax containing embedded Grubbs' catalyst are generated by congealing a molten aqueous suspension. Even with a ten-fold reduction in catalyst concentration from previous systems, these microspheres produce unprecedented levels of toughness recovery in a polymeric self-healing material (see Figure). Unli…
Bacterial-cellulose nanofibers obtained from Acetobacter xylinum can reinforce polymer resins while maintaining the transparency of the original resin, even at fiber contents as high as 70 wt.-%, because the nanofibers do not appreciably scatter visible light. The flexible plastic composites (see Figure) reinforced wi…