Near infrared electroluminescence from neodymium complex-doped polymer light emitting diodes

Organic light emitting diode devices employing organometallic Nd(9-hydroxyphenalen-1-one)(3) complexes as near infrared emissive dopants dispersed within poly(N-vinylcarbazole) (PVK) host matrices have been fabricated by spin-casting layers of the doped polymer onto glass/indium tin oxide (ITO)/3,4-polyethylene-dioxythiophene-polystyrene sulfonate (PEDOT) substrates. Room temperature electroluminescence, centered at similar to 1065 nm. was observed from devices top contacted by evaporated aluminum or calcium metal cathodes and was assigned to transitions between the F-4(3/2) -> I-4(11/2) levels of the Nd3+ ions. In particular, a near infrared irradiance of 8.5 nW/mm(2) and an external quantum efficiency of 0.007% was achieved using glass/ITO/PEDOT/PVK:Nd(9-hydroxyphenalen-1-one)(3)/Ca/Al devices. (c) 2005 Elsevier B.V. All rights reserved.

Electronic Structure of an XUV Photogenerated Solid-Density Aluminum Plasma

By use of high intensity XUV radiation from the FLASH free-electron laser at DESY, we have created highly excited exotic states of matter in solid-density aluminum samples. The XUV intensity is sufficiently high to excite an inner-shell electron from a large fraction of the atoms in the focal region. We show that soft-x-ray emission spectroscopy measurements reveal the electronic temperature and density of this highly excited system immediately after the excitation pulse, with detailed calculations of the electronic structure, based on finite-temperature density functional theory, in good agreement with the experimental results.

Thermal study of selectively plated nickel sulfamate coatings

Nickel sulfamate solution was applied to mild steel substrates by the process of selective plating. The coated samples were heated to temperatures in the range of 50–1000 °C. Thermal analysis, X-ray diffraction and microscopy techniques were used to investigate the effect of secondary heating on the microstructure, mechanical properties and the composition of the surface coatings.

The microscopy analysis showed that the secondary heating caused diffusion within the coating itself and diffusion between the coating and the substrate as concentrations of iron increased in the coating and nickel appeared in the substrate. This diffusion redistribution also caused a phase transformation in the coating as NiO formed on the surface when the coating was heated in a furnace fitted with a nitrogen flow. However this transformation was found not to occur when the coating was heated in a sealed helium environment. Layer and grain growth occurred as temperature increased with the grains taking their preferred orientation as they were heated.

The surface hardness was found to initially rise up from 565 HV to 600 HV when heated to 200 °C. After 200 °C the surface hardness decreased in two stages before falling to 110 HV by 1000 °C. During tensile testing the coated samples performed marginally better in tension than the uncoated samples, however the temperatures used were not elevated high enough to show any real degradation during the tensile testing of the nickel coating that was shown during hardness testing and the microscopy analysis

SEM-EDX of morphology of electroless nickel coatings with tin and tungsten

Electroless plating of binary Ni-P, ternary Ni-Sn-P and Ni-W-P, and quaternary Ni-W-Sn-P alloy coatings was carried out in alkalicitrate baths. After the plating, several kinds of test were carried out to determine the improvement in the characteristics and properties due to the additional elements as well as to study the change in behaviour when heat treatment was applied to these coatings. The coatings were subjected to X-ray diffraction analysis where it was found that all the coatings were amorphous. Interesting surface morphology features were examined using scanning electron microscopy. Addition of a third element improved the hardness.

Extracting a more realistic pseudopotential for aluminum, lead, niobium and tantalum from superconductor electron tunnelling spectroscopy data

Electron tunnelling spectroscopy, developed to extract superconductive metals the electron-phonon spectral density, $\alpha^2F(\nu)$, is found to be a powerful tool also for extracting a more realistic pseudopotential from such metals. The pseudopotential so extracted has a range of surprising but physically reasonable properties and regenerates $\alpha^2F(\nu)$ accurately. Free from most of its long-standing uncertainties, thie pseudopotential may be useful in a number of active fields.

Thin catalytic coatings on microreactor walls A way to make industrial processes more efficient

Current trends in the development of microstructured reactors with thin catalytic films (from 100 nm up to several microns) that have self-assembled nanostructures are discussed. A major technique that is used to prepare such films is sol-gel processing. This involves depositing a complex fluid on a microstructured substrate by dip, spin, or spray coating, followed by surfactant removal to form the porous nanostructures. A novel methodology has been developed by which a uniform coating containing controlled amounts of (poly) metallic nanoparticles can be obtained. This elegant strategy is based on the condensation of metal oxide species by self-assembly in the presence of metallic colloids. The potential microreactor applications brought forth by this innovative protocol are placed in perspective in the light of its versatility.

Catalytic Mo2C coatings for the water gas shift reaction: Electrosynthesis in molten salts

Electrosynthesis methods using molten salts are suggested for obtaining a new catalytic system based on the Mo2C/Mo composition for the water gas shift reaction. The coatings obtained by the discharge of the carbonate ion on a molybdenum substrate and by the simultaneous reduction of the electroactive species MoO42 and CO32- are catalytically more active than bulk Mo2C or the commercial catalyst Cu-ZnO-Al2O3 by one and three orders of magnitude, respectively.