Materials Literature
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We measured the ultrafast response of triangular silver nanoparticles upon femtosecond excitation of their plasmon resonance. After a fast electron relaxation, the signature of a bimodal mechanical vibration of the particle is apparent as a spectral modulation. We identify the two lowest frequency, totally symmetric v…
Femtosecond visible photoluminescence is detected from gold nanoparticles using time-resolved fluorescence upconversion spectroscopy. We directly compared this fast luminescence from gold nanospheres $(\ensuremath{\emptyset}25\phantom{\rule{0.3em}{0ex}}\mathrm{nm})$ with that obtained from nanorods ($\ensuremath{\empt…
The oxidation of formic acid and carbon monoxide was studied at a gold electrode by a combination of electrochemistry, in situ surface-enhanced Raman spectroscopy (SERS), differential electrochemical mass spectrometry, and first-principles DFT calculations. Comparison of the SERS results and the (field-dependent) DFT…
We present a detailed numerical study of effective interactions between micrometer-sized silica spheres, induced by highly charged zirconia nanoparticles. It is demonstrated that the effective interactions are consistent with a recently discovered mechanism for colloidal stabilization. In accordance with the experimen…
Structural and upconversion emission properties of ZrO2:Yb3+–Ho3+ nanocrystals were analyzed as function of Yb3+ concentration. Structural characterization shows a crystallite size up to 80 nm and tetragonal and cubic phase as the main crystalline structures. Strong green (540 nm) and weak red (670 nm) and near infrar…
Pr 3 + -doped PbO–GeO2 (PGO) glasses containing silver nanoparticles (NPs) were prepared and their spectroscopic characteristics were studied. The PGO samples and the nucleation of silver NP were obtained melting the starting oxide powders, quenching and annealing. Transmission electron microscopy was used to characte…
In this letter, we report the discovery of superconductivity in Li3Ca2C6. Several graphite intercalation compounds (GICs) with electron donors, are well known as superconductors. It is probably not astonishing, since it is generally admitted that low dimensionality promotes high superconducting transition temperatures…
We report a method for fabricating nanogaps directly with electron beam lithography (EBL). The primary resolution-limit of EBL, electron back-scattering, is reduced dramatically by using a thin-film as a substrate. We show that this resolution enhancement allows one to fabricate metal electrodes with separation from a…
We have studied the photoexcited carrier relaxation dynamics in the Kondo insulator SmB6 and the heavy fermion metal YbAgCu4 as a function of temperature and excitation level. The dynamic response is found to be both strongly temperature dependent and nonlinear. The data are analyzed with a Rothwarf-Taylor bottleneck…
The investigation of small size embedded nanostructures, by a combination of complementary anomalous diffraction techniques, is reported. GaN Quantum Dots (QDs), grown by molecular beam epitaxy in a modified Stranski-Krastanow mode, are studied in terms of strain and local environment, as a function of the AlN cap lay…
The response of polar nanoregions (PNR) in the ferroelectric relaxor $\mathrm{Pb}[{({\mathrm{Zn}}_{1∕3}{\mathrm{Nb}}_{2∕3})}_{0.92}{\mathrm{Ti}}_{0.08}]{\mathrm{O}}_{3}$ subject to a [111]-oriented electric field has been studied by neutron diffuse scattering. Contrary to classical expectations, the diffuse scattering…
Transparent polymers were reinforced by bacterial cellulose (BC) nanofibers, which are 10×50nm ribbon-shaped fibers. They exhibited high luminous transmittance at a fiber content as high as 60 wt %, and low sensitivity to a variety of refractive indices of matrix resins. Due to the nanofiber size effect, high transpar…
We have investigated the growth of antiferromagnetic Mn3N2(001) on MgO (001) by molecular beam epitaxy and scanning tunneling microscopy . The images show smooth terraces and atomic steps. On some of the terraces a unique and new reconstruction is seen, resolved as square Mn tetramers in a c(4x2) structural arrangemen…
We study how confining the equilibrium hard-sphere fluid to restrictive one- and two-dimensional channels with smooth interacting walls modifies its structure, dynamics, and entropy using molecular dynamics and transition-matrix Monte Carlo simulations. Although confinement strongly affects local structuring, the rela…
Let's twist again: Transcription of molecular chirality from common stereogenic centers to amplified supramolecular chirality during the coassembly of gel-forming π-conjugated molecules by inverted helicity results in the formation of longitudinally fused M and P helices. This “sergeants and soldiers” approach to coas…
A strictly heterodinuclear Cu-Tb complex [LCu(O(2)COMe)Tb(thd)(2)] made with a Schiff base L, thd, and monomethylcarbonate ligands [L(2-) = N,N'-2,2-dimethylpropylenedi(3-methoxysalicylideneiminato); thd = tetramethylheptanedionato] behaves like a single-molecule magnet. The monomethylcarbonate ligand, which appears d…
Playing the platinum card: By means of a self-organization process at low temperature in organic solvent, porous platinum nanoparticles of excellent dispersity have been prepared. The particles are obtained as flowerlike arrays (see TEM image), and their porosity was shown to be similar to other mesoporous Pt systems.…
Abstract Nanocomposites of chitosan and nanoclays (MMT‐Na + and Cloisite 30B) were prepared by solvent casting. The structural properties, thermal behaviors, and mechanical properties were characterized using X‐ray diffraction (XRD), transmission electron microscopy (TEM), atomic force microscopy, differential scannin…
We present results of an ab initio density-functional theory study of three bismuth-based multiferroics, $\mathrm{Bi}\mathrm{Fe}{\mathrm{O}}_{3}$, ${\mathrm{Bi}}_{2}\mathrm{Fe}\mathrm{Cr}{\mathrm{O}}_{6}$, and $\mathrm{Bi}\mathrm{Cr}{\mathrm{O}}_{3}$. We disuss differences in the crystal and electronic structure of th…
Polyaniline nanofibers are shown to form spontaneously during the chemical oxidative polymerization of aniline. The nanofibrillar morphology does not require any template or surfactant, and appears to be intrinsic to polyaniline synthesized in water. Two approaches--interfacial polymerization and rapidly-mixed reactio…