Materials Literature
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We propose a novel strategy using fullerenes for the construction of solar energy conversion systems that mimic the primary electron transfer events in photosynthesis. Redox-active fullerenes such as C60 and C70 were covalently bound to a porphyrin and the photophysical properties of the resulting compounds were inves…
X-ray-diffraction studies of nanometer-sized particles of zinc sulfide show a significant reduction in the zinc-blende-to-wurtzite phase transition temperature, as compared to the bulk value. Five nanoparticle samples were annealed in vacuum at temperatures increasing from room temperature (23 \ifmmode^\circ\else\text…
A metal nanoshell consists of a nanometer-scale dielectric core surrounded by a thin metallic shell. The plasmon resonance of metal nanoshells displays a geometric tunability controlled by the ratio of the core radius to the total radius. For gold-coated Au2S this ratio varies from 0.6 to 0.9, yielding a plasmon reson…
The advantages of combining carbon nanotubes with conjugated polymers for high-efficiency photovoltaic devices are explored in this article. The preparation and optical properties of a composite of multiwalled carbon nanotubes (MWNTs) and poly(p-phenylene vinylene) (PPV) are reported and the efficiency of a photovolta…
Tailoring of porous materials involves not only chemical synthetic techniques for tailoring microscopic properties such as pore size, pore shape, pore connectivity, and pore surface reactivity, but also materials processing techniques for tailoring the meso- and the macroscopic properties of bulk materials in the form…
The application of broken symmetry density functional calculations to homobinuclear and heterobinuclear transition metal complexes produces good estimates of the exchange coupling constants as compared to experimental data. The accuracy of different hybrid density functional theory methods was tested. A discussion is…
It has been shown recently that in many cases strain anisotropy in powder diffraction can be well accounted for by the dislocation model of the mean square strain. The practical application assumes knowledge of the individual contrast factors C of dislocations related to particular Burgers, line and diffraction vector…
X-ray diffraction images from two-dimensional position-sensitive detectors can be characterized as thick or thin, depending on whether the rotation-angle increment per image is greater than or less than the crystal mosaicity, respectively. The expectations and consequences of the processing of thick and thin images in…
Novel organic−inorganic hybrid mesoporous materials have been synthesized, in which organic and inorganic oxide moieties are distributed homogeneously at the molecular level in the framework, forming a covalently bonded network. They are highly ordered at the mesoscale, with two- and three-dimensional hexagonal symmet…
Nabiasite, ideally BaMn 9 [(V,As)O 4 ] 6 (OH) 2 , is a new mineral which occurs in rhodochrosite-, friedelite- and barite-bearing veinlets crosscutting Mn ores at the historic Pla de Labasse deposit near the Nabias hamlet, Central Pyrenees, France. These syn-genetic exhalative ores are embedded in Lower Carboniferous…
A helium-gas-pressure apparatus with optical-reflectivity detection tested with a spin-transition solid, Jelena Jeftic, Nieves Menéndez, AndréWack, Epiphane Codjovi, Jorge Linarès, Antoine Goujon, Gérard Hamel, Stefan Klotz, Gérard Syfosse, François Varret
The energy dissipation of Tb 3+ /Eu 3+ cations in both heterolanthanide multinuclear polyoxometalates, K 15 H 3 [Tb 1.4 Eu 1.6 (H 2 O) 3 (SbW 9 O 33 )(W 5 O 18 ) 3 ]·25.5H 2 O and Na 7 H 19 [Tb 4.3 Eu 1.7 O 2 (OH) 6 (H 2 O) 6 Al 2 (Nb 6 O 19 ) 5 ]·47H 2 O is studied by crystal structures, emission and excitation spect…
High molecular weight poly( l -glutamic acid) was chemically modified with a spiropyran reagent to give polypeptides containing 35 and 85 mol % spiropyran units in the side chains. To investigate the photochromic and conformational behavior in acid conditions, the polypeptides were dissolved in hexafluoro-2-propanol (…
A new diamine, bis[4-(4-aminophenoxy)phenyl]diphenylmethane (BAPDM ), bearing diphenylmethylene linkage was prepared starting from bis(4-hydroxyphenyl)diphenylmethane. The diamine was reacted with various aromatic dicarboxylic acids to obtain a series of new polyamides with moderate to high inherent viscosities of 0.6…
The reduction of chloroaurate and the incorporation of Au clusters in polyaniline, PANI, films have been investigated. The chloroaurate complex is generated at the electrode surface during Cl - doping of Au/PANI. FTIR and UV/vis data indicate that chloroaurate interacts with PANI and that its reduction to metallic Au…
The theoretical treatment of the evolution of a dislocation ensemble in a plastically deformed real crystal is discussed. Kinetic equations for the dislocation density are formulated which include elementary dislocation processes (source generation, immobilization, multiplication, annihilation, and diffusion) and on t…
Cathodic electrodeposition in an aqueous mixed solution of zinc nitrate and water-soluble tetrasulfonated metallophthalocyanines (TSPcMs), in which M = Zn(II) (TSPcZn), Al(III)[OH] (TSPcAl), or Si(IV)[OH] 2 (TSPcSi), resulted in a self-assembled growth of zinc oxide (ZnO) thin films whose surface is modified by TSPcMs…
Light absorption at the boundary of indirect-band-gap and direct-forbidden gap semiconductors is analyzed. It is found that the possibility of the electron momentum nonconservation at the interface leads to essential enhancement of absorption in porous and microcrystalline semiconductors. The effect is more pronounced…
We use empirical molecular dynamics technique to study the low-energy vibrations in a large 4096 atom model for pure amorphous silicon and a set of models with voids of different size based on it. Numerical vibrational eigenvalues and eigenvectors for our models are obtained by exact diagonalization of their dynamical…
I discuss the properties of electron states in amorphous Si based on large scale calculations with realistic several thousand atom models. A relatively simple model for the localized to extended (Anderson) transition is reviewed. Then, the effect of thermal disorder on localized electron states is considered. It is fo…