Oleg V. Salata

Abstract Manmade nanoparticles range from the well-established multi-ton production of carbon black and fumed silica for applications in plastic fillers and car tyres to microgram quantities of fluorescent quantum dots used as markers in biological imaging. As nano-sciences are experiencing massive investment worldwide, there will be a further rise in consumer products relying on nanotechnology. While benefits of nanotechnology are widely publicised, the discussion of the potential effects of their widespread use in the consumer and industrial products are just beginning to emerge. This review provides comprehensive analysis of data available on health effects of nanomaterials.

Liquids can readily interact with electric fields. Field-induced or injected charges in liquids interact with an external electric field causing liquids to move, break into drops or spray into jets or strings of fine droplets. One important case of liquid in the capillary deserves special mentioning as it serves as a basis of many and varied technological applications. An electric field acts on a liquid meniscus, counteracted by surface tension. In a strong enough field a cone is formed that emits a jet of liquid from its tip. This effect is used, for example, to coat car bodies by a thin uniform layer of paint. At the other end of the scale nano-electrospray has revolutionised mass-spectroscopy of bio-molecules. The ability of electrospray to repeatedly generate very small and uniform volumes of liquid makes it into one of the important tools of nanotechnology. Electrospray has been used to deposit ultra-thin films of inorganic, organic and biological materials, to generate nanoparticles and quantum dots, to sort them according to their sizes, and to help with dispersion and delivery of nanomaterials. This mini-review introduces basics of electrospray technology and summarises the diverse applications of electrospray in nano-sciences.

A new, highly luminescent terbium complex (see Figure) is investigated here as a material for organic light-emitting diodes (OLEDs). It is demonstrated that device efficiencies of over 2.6 lm/W are possible—the highest yet reported for a lanthanide-based OLED. This indicates that lanthanide-based materials are a viable alternative to Alq- and PPV-based polymers for use in commercial OLED displays.

The influence of plasma oxidation and other surface pretreatments on the electronic structure of indium–tin–oxide (ITO) thin films has been studied by high resolution x-ray photoemission spectroscopy. Plasma oxidation compensates n-type doping in the near surface region and leads to a reduction in the energy of plasmon satellite structure observed in In 3d core level spectra. In parallel, the Fermi level moves down within the conduction band, leading to a shift to low binding energy for both core and valence band photoemission features; and the work function increases by a value that corresponds roughly to the core and valence band binding energy shifts. These observations suggest that the conduction band of ITO is fixed relative to the vacuum level and that changes of work function are dominated by shifts of the Fermi level within the conduction band.

Divalent molecular lanthanide complexes are shown to offer promise as tunable light emitting materials in thin film electroluminescent displays for the first time in this study. Bright orange luminescence is obtained from thin film EL device structures containing bis[tris(dimethylpyrazolyl)borate]europium(II) (1), which has a high quantum efficiency in the solid state. The effect of device structure upon device efficiency and light purity is discussed and an optimum EL device structure for 1 detailed.