Nitrides/oxynitrides have been recently focused for various applications including visible-light responding photocatalysis, electrocatalysis, photoluminescence, and ion battery. Although morphological control, especially nanostructurization, of nitrides/oxynitrides can improve the catalytic activities due to exposure of exotic crystal planes and increase of reactive sites, nanostructurization of nitrides/oxynitrides has not been facile. Here, we introduce our developments for nanostructurization of wurtzite oxynitrides by nitridation of the precursor oxides with nanostructures obtained hydrothermally. The use of precursor oxides with nanostructures was advantageous for acquisition of not only nanostructured oxynitrides as well as transparent oxynitrides films. Our results show that the crystal structures of precursor oxides largely affect the retention degree of the precursor nanostructure and the crystallinity in the obtained oxynitrides. This indicates that understanding the relationship between crystal structures before and after nitridation will lead to nanostructured oxynitrides' design.
Recent advances in nanotechnology has opened vast applications for nanometre-sized metal particles, especially in industrial and biomedical fields. In order to stably exhibit properties unique to this class of materials, surface modification using an appropriate selection of polymers is crucial. In this study, the cyclic analogue of poly(ethylene glycol) (c-PEG) was used to stabilize gold nanoparticles (AuNPs) through physisorption. When compared to its linear counterparts, c-PEG was found to grant vastly enhanced dispersion stability of AuNPs against various experimental procedures and environments, such as freezing, lyophilization, heating, and physiological conditions. Interestingly, the dispersion stabilizing effect of c-PEG exceeded even that of thiolated PEG (HS–PEG–OMe). Animal experiments further revealed extended blood circulation and enhanced tumour accumulation in mice for c-PEG-stabilized AuNPs. These results suggest the topology-enhanced physisorption of c-PEG on AuNPs endow sufficient dispersion stability towards biomedical applications, thus presenting an alternative method to the conventional gold–sulfur chemisorption.
Metal fine particle / nanoparticle-based conductive inks and pastes have attracted much attentions for modern manufacturing electronic devices. Printing of these materials and sintering gives conductive patterns, which is called as printed electronics (PE). Especially, development of such inks or pastes which can be sintered at a low temperature is indispensable to realize printed electronics technology on flexible polymer substrates. In this paper, we treated copper fine particles and nanoparticles for PE. Copper is a promising material due to its low cost and electro-migration resistance.