Surface-enhanced luminescence from Eu

The effect of colloidal dispersion of silver on the luminescent properties of Eu (III) complex with pyridine-3,5-dicarboxylic acid (PyDC) was investigated. The luminescence from Förster type europium complex was enhanced several times with the presence of Ag colloid and the enhancement factor showed Ag concentration dependence. The observed enhancement effect was discussed in view of surface-enhancement effect and optical absorption due to surface plasmon resonance, both arising from excitation of surface plasmon polariton. The coordination structure around Eu (III) ion was also affected with the presence of Ag colloid, which induced the change in the intensity ratio between two emission bands of
$\rm {}^{5}D_{0} \rightarrow {}^{7}F_{1}$ 
and $\rm {}^{5}D_{0} \rightarrow {}^{7}F_{2}$ transitions of Eu (III) ion

Composition dependence on dispersion of Au/Cu bimetallic nanoparticles in nylon 11 thin films

Effect of composition on the dispersion of AuxCu$_{1-x}$ bimetallic nanoparticles into nylon 11 matrix has been investigated. TEM, EDX, and XPS depth profiling were used for characterizing the changes in the composition of the bimetallic particles and in the depth distribution of the particles in the nylon 11 layer caused by heat treatment in N2 atmosphere. The island-like bimetallic particles were found to be formed on the nylon 11 surface before heat treatment. The results of XPS depth profiling revealed that, by the heat treatment, the AuxCu$_{1-x}$ bimetallic particles with $x\leq0.55$ were not dispersed into the nylon 11 layer while those with $x\geq0.70$ were homogeneously dispersed in the films, indicating the existence of critical composition for penetration of the bimetallic particles. By comparing the composition and structure of the bimetallic particles, the cause of these finding is discussed in terms of surface free energy of the particles

Preparation of Cu

Small Copper (I) oxide, Cu2O, nanoparticles dispersed in diamine-terminated polyethyleneoxide (PEO-NH2) matrix have been successfully prepared by vacuum evaporation of copper onto the molten PEO-NH2. The obtained composite were characterized by TEM, electron diffraction, TG-DTA and FT-IR spectroscopy. The stable composite, in which the Cu2O nanoparticles are stabilized through interaction between DNH2 chain end groups of PEO molecules and Cu2O nanoparticles was obtained when the samples were heat-treated at 110 $^{\circ}$C. The mean size of the Cu2O nanoparticles increased from 2.5 to 3.5 nm in diameter upon increasing the amount of initial Cu deposition. The obtained composite material having a waxy texture was soluble in many solvents without aggregation and can be handled as a simple chemical compound for starting material in various applications