Materials Literature
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Using videomicroscopy data of a two-dimensional colloidal system the bond-order correlation function G{6} is calculated and used to determine both the orientational correlation length xi{6} in the liquid phase and the modulus of orientational stiffness, Frank's constant F{A}, in the hexatic phase. The latter is an ani…
The synthesis and characterization of water-soluble nitric oxide (NO)-releasing monolayer-protected gold clusters (MPCs) are reported. Tiopronin-protected MPCs ( approximately 3 nm) were functionalized with amine ligands and subsequently exposed to 5 atm of NO to form diazeniumdiolate NO donors covalently bound to the…
Small angle neutron scattering studies on polystyrene loaded with spherical silica nanoparticles under contrast-matched conditions unequivocally show that chain conformations follow unperturbed Gaussian statistics independent of chain molecular weight and filler composition. Liquid state theory calculations are consis…
Farbenfroh: Durch Einstellen der Elektronendonoreigenschaften des π-konjugierten Bithiophen-Gerüsts wurden intensiv emittierende Festkörper erhalten, deren Maxima einen großen Teil des sichtbaren Spektrums abdecken (siehe Bild). Eine tiefrote Fluoreszenz mit großer Stokes-Verschiebung um 200 nm resultiert aus einem in…
Novel hybrid triphenylene-carbosiloxane liquid crystalline monomers and star-shaped oligomers have been synthesized and their thermal behavior and liquid-crystalline properties analyzed and characterized. All compounds exhibit a columnar hexagonal phase and show, particularly the oligomers, a small tendency to crystal…
Photodynamic therapy (PDT) is a noninvasive treatment of some diseases including cancer. We have developed poly(ethylene glycol) (PEG)-attached dendrimers as a drug-carrier candidate. In this study, we prepared nanocapsules of photosensitizers using PEG-attached dendrimers for application to PDT. Two PEG-attached dend…
Zinc stannate (Zn 2 SnO 4 ) particles with 27-nm size were synthesized by hydrothermal treatment. Nanoporous Zn 2 SnO 4 thin films were prepared on conducting glass substrates and used as working electrodes in dye-sensitized solar cells, DSSC. Their behavior was compared with standard TiO 2 cells, using (TBA) 2 -cis -…
We measure the magnetic damping parameter a in thin film CoFeB and permalloy (Py) nanomagnets at room temperature using ferromagnetic resonance driven by microwave frequency spin-transfer torque. We obtain $α_{CoFeB} = 0.014 \pm 0.003$ and $α_{Py}=0.010 \pm 0.002$, values comparable to measurements for extended thin f…
We present spectral measurements of spin-wave excitations driven by direct spinpolarized current in the free layer of nanoscale Ir20Mn80/Ni80Fe20/Cu/Ni80Fe20 spin valves. The measurements reveal that large-amplitude coherent spin wave modes are excited over a wide range of bias current. The frequency of these excitati…
The orbital contribution to the magnetic properties of Fe in systems of decreasing dimensionality (bulk, surfaces, wire and free clusters) is investigated using a tight-binding hamiltonian in an $s, p,$ and $d$ atomic orbital basis set including spin-orbit coupling and intra-atomic electronic interactions in the full…
Graphite is an example of a layered material that can be bent to form fullerenes which promise important applications in electronic nanodevices. The spheroidal geometry of a slightly elliptically deformed sphere was used as a possible approach to fullerenes. We assumed that for a small deformation the eccentricity of…
We investigate the current-voltage characteristics of a II-VI semiconductor resonant-tunneling diode coupled to a diluted magnetic semiconductor injector. As a result of an external magnetic field, a giant Zeeman splitting develops in the injector, which modifies the band structure of the device, strongly affecting th…
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 explains what TDDFT is, and how it differs from ground-state DFT. We show the basic formalism, and illustrate with simple exam…
This paper is aimed at presenting a simple vibronic model for describing the dipolar reorientation in crystals by means of reaction rate theory. The Hamiltonian of an isolated dipole is simplified so as to render the problem solvable. Depending on the crossover splitting the dipoles may reorientate adiabatically with…
We report a metallic state in a nanostructured porous crystal 12CaO x 7Al2O3 by incorporating electrons in the inherent subnanometer-sized cages, in which a three-dimensionally closely packed cage structure acts as an electronic conduction path. High-density electron doping ( approximately 2 x 10(21) cm(-3)), which wa…
The synthesis and characterization of a new nitric oxide (NO)-releasing scaffold prepared from amine-functionalized silica nanoparticles are reported. Inorganic-organic hybrid silica was prepared via cocondensation of tetraethoxy- or tetramethoxysilane (TEOS or TMOS) and aminoalkoxysilane with appropriate amounts of e…
Silver nanocubes with sharp or truncated corners were synthesized, deposited on silicon substrates, and functionalized with Raman-active thiols for surface-enhanced Raman scattering (SERS) studies. The use of substrates with registration marks allowed us to correlate the SERS spectra from individual nanocubes to their…
Seeing the light: Tuning the electron-donating ability of the π-conjugated framework of bithiophene has resulted in intense solid-state emissions with maxima ranging over a wide visible region (see picture). Even a deep-red fluorescence with a large Stokes shift close to 200 nm, arising from the intramolecular charge-…
Pure Na0.44MnO2 samples were prepared via a solid-state route by carefully tuning the synthesis conditions. Insertion/deinsertion of sodium into the well-crystallized particles leads to capacities as high as 140 mA.h/g. A potentiostatic intermittent titration technic, together with in situ X-ray diffraction measuremen…
We studied the nucleation of gold clusters on TiO2(110) surfaces in three different oxidation states by high-resolution scanning tunneling microscopy. The three TiO2(110) supports chosen were (i) reduced (having bridging oxygen vacancies), (ii) hydrated (having bridging hydroxyl groups), and (iii) oxidized (having oxy…