Materials Literature
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We calculate the electronic and optical excitations of polythiophene using the GW approximation for the electronic self-energy, and include excitonic effects by solving the electron-hole Bethe-Salpeter equation. Two different situations are studied: excitations on isolated chains and excitations on chains in crystalli…
ultiwalled carbon nanotubes, prepared by both electric arc discharge and chemical vapor deposition methods, show a strong visible light emission in photoluminescence experiments. All the samples employed in the experiments exhibit nearly same super-linear intensity dependence of the emission bands on the excitation in…
Several alumina-supported ceria samples with varying ceria contents (1, 2, 10, and 39 wt %) have been studied by different techniques (XRD, Raman, TEM-EDS, UV−vis DRS, XANES, and EPR), aiming to establish a complete model on the structural and redox characteristics of ceria entities in these samples. Two general types…
Recent advances in CVD diamond growth and processing technology allow this material to be used effectively in a number of high-power laser applications. New data will be presented on the optical properties at 10.6 micrometer relevant to the use of CVD diamond as optical elements in high-power CO<SUB>2</SUB>, lasers. I…
Abstract Foam propagation in co-injection was studied in a 10 m long porous medium, equipped with pressure ports for every 1 m. The porous medium had been characterized by flooding experiments on the core scale. In the absence of oil, propagation on the 10 m scale could be understood by corescale, steady-state foam pr…
The oxidative polymerisation of the complex2,3-dimethyl-N,N′-bis(salicylidene)butane-2,3-diaminatonickel(II), [Ni(saltMe)], was monitored by the electrochemical quartz microbalance (EQCM) and crystal impedance techniques. Polymerisation efficiency was maintained throughout deposition of a film, which behaved rigidly,…
p-type lead sulphide (PbS) thin films were chemically deposited onto Si3N4/n-Si substrates. A three-contact pseudo-metal–oxide–semiconductor structure was designed in order to investigate the possibility of enhancing the signal-to-noise ratio in the PbS film by field effect. It was proved that on the entire sensitivit…
Der photo- und redoxaktive Diazaligand 1 und sein zweifach alkyliertes Derivat 2 wurden ausgehend von Perylenbisimiden erhalten. Die Eignung von 1 zum Aufbau supramolekularer Architekturen wurde anhand des Bindungsverhaltens gegenüber Carbonsäuren, Zinkporphyrinen und Metallionen belegt.
The oxidative polymerisation of the complex2,3-dimethyl-N,N'-bis-(salicylidene)butane-2,3-diaminatonick-el(II), [Ni(saltMe)], was monitored by the electrochemical quartz microbalance (EQCM) and crystal impedance techniques. Polymerisation efficiency was maintained throughout deposition of a film, which behaved rigidly…
The dielectric behavior of SrTiO3 single crystals under high dc electric field (up to 50 kV/cm) is reported in this letter. The rounded dielectric constant peaks are induced by the application of dc bias, and the corresponding dielectric losses are observed. The results show that dielectric loss under dc bias consists…
The “dynamic spatial demand” of Fréchet-type dendrons is compared with that of “conventional” building blocks by evaluation of the deslipping behavior of dendritic rotaxanes (see picture). This method leads to a ranking list of the size of voluminous building blocks, which will be useful for the rating of steric effec…
Der vollständig ladungsgetrennte Zustand PH2+-[Ir]-PAu− wird mit 50 % Effizienz nach der Anregung der freien Porphyrinbase PH2 in 1 gebildet, indem sich sukzessive Elektronentransfers zur Bis(terpyridin)iridium-Einheit [Ir] und zum Goldporphyrin PAu anschließen. Die Desaktivierung dieses Zustands erfolgt quantitativ ü…
A series of extended tetrathiafulvalene (TTF) derivatives bearing one or two 1,4-dithiafulven-6-yl substituents has been prepared. The new compounds present remarkable electrochemical singularities compared with other TTF derivatives, which are strongly affected by the nature of the substitution on the lateral heteroc…
Resonant x-ray diffraction was carried out at the Se K edge in thick free-standing films of a selenophene liquid crystalline material, revealing detail of the structure of the ferro-, ferri-, and antiferroelectric phases. The ferrielectric phase was shown to have a three-layer superlattice. Moreover, the structure of…
The mesoporous high surface area MCM-41 material was synthesized and used as a support material for the preparation of Co/MCM-41 samples. Co 2 (CO) 8 was deposited from the gas phase onto the MCM-41 surface in a fluidized bed reactor. Pure MCM-41 and Co/MCM-41 samples were characterized by various spectroscopic and an…
Eine zeolithartige offene Gerüststruktur, die in zwei zueinander senkrechten Richtungen mit weiten Kanälen durchsetzt ist – dies ist das Kennzeichen einer aus Metalloporphyrin-Bausteinen erhaltenen faszinierenden supramolekularen Anordnung (siehe Bild). Nur 42 % des Kristallvolumens sind ausgefüllt, sodass das Gerüst…
Upon irradiation, reversible modulation of triple-helix formation occurs. A model double helix is formed from oligo(T) and oligo(dA). In the presence of a second oligo(T) modified with an azobenzene moiety, the binding strength of the triple helix is dependent upon the configuration of the azobenzene, a feature contro…
A fully charge-separated state PH2+-[Ir]-PAu− is formed with 50 % efficiency following excitation of the free-base porphyrin component PH2 of 1 by successive electron transfers to the iridium bis(terpyridine) moiety [Ir] and the gold porphyrin PAu. Its deactivation proceeds quantitatively through the triplet state 3PH…
A uniquely structured molecular solid composed of pillared bilayers of metalloporphyrin building blocks has been formulated. It consists of a single three-dimensional multicomponent supramolecular framework, resembling a zeolite, which accounts for only 42 % of the crystal volume (see picture). The spacious, open gall…
Highly conductive perovskite La0.5Sr0.5CoO3 thin films were grown on (012) LaAlO3 by pulsed-laser deposition at different substrate temperatures. Magnetoresistance (MR) measurements show only a negative effect for the films grown at a temperature of 800 °C. However, a positive MR effect was found for the films grown a…