Synthesis of Fe3O4-ZnS/AgInS2 composite nanoparticles using a hydrophobic interaction.

Magnetic nanoparticles and fluorescent quantum dots (QDs) can make many effective applications in biomedical system. Here, we demonstrated one way of synthetic method and its surface modification to use for biomedical applications. Fe3O4 nanoparticles are well known as magnetic materials and its magnetic property can be used in magnetic resonance imaging (MRI), cell detection. QDs as a fluorescent probes, make cell labeling and in vivo imaging possible. ZnS/AgInS2 QDs have a lower toxicity than other QDs (CdSe, CdTe, CdS). We combined two nanoparticles by hydrophobic interaction in their ligands. The prepared fluorescent magnetic composite particles were modified with CTAB-TEOS. The surface modified composite has a low cytotoxicity and these biocompatible particles will provide many possibilities in biomedical system.

A novel synthetic method of Sr2Si5N8:Eu2+ from SrSi2O2N2:Eu2+ by carbo-thermal reduction and nitridation.

We demonstrated a novel synthetic route from Eu(2+)-doped oxy-nitride phosphors to prepare Eu(2+)-doped nitride phosphors. The Eu(2+)-doped Sr2Si5N8 phosphor was prepared by carbo-thermal reduction and nitridation from Eu(2+)-doped SrSi2O2N2 mixed with carbon. Eu(2+)-doped SrSi2O2N2 phosphor was prepared at 1350-1500 degrees C, and subsequently Eu(2+)-doped Sr2Si5N8 phosphor was synthesized at 1550-1700 degrees C. When over 4 wt% of carbon was added, the phase of SrSi2O2N2:Eu2+ changed to the one of Sr2Si5N8:Eu2+. The data of photoluminescent spectra and X-ray powder diffraction (XRD) patterns proved the phase transition. The product showed a red emission of 616 nm at the blue excitation of 450 nm. The shape of phosphor changed from a plate type to a rod one. We also prepared some red phosphors of SrSi(x)O(o)N(n):Eu2+ according to the different ratio of Si. Although the Si content was different from each other, there was no change in XRD patterns.