Synthesis And Surface Plasmon Resonance Of Copper Nanoparticles

Compared to the bulk elements, nano-sized metal nanoparticles exhibit unique optical, electrical, magnetic, mechanical and catalytic properties. Based on their unique properties, metal nanoparticles have been widely applied in the fields of cancer therapeutics, biological sensors, nanoscale optical devices, surface-enhanced fluorescence and surface-enhanced raman spectroscopies. The surface plasmon resonance (SPR) is one of the most concerned research focus among all these properties. The optical nonlinear phenomena could be observed obviously around the absorption peak, due to the surface plasmon resonance. The SPR is very sensitive to the size, shape, dielectric properties of the nanoparticles and dielectric environment. Synthesizing metal nanoparticles with different morphologies has received more attention, because the morphology of nanoparticles is one of the main factors affecting the features.Copper nanoparticles embedded in BK7 glasses have been prepared with hydrothermal method and ion-exchange method following by reducing in H2, respectively. Their surface morphologies, crystal structures, and optical properties have been characterized and investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), UV-Vis absorption and fluorescence (FL) spectrophotometers.SEM images showed that the prepared copper nanoparticles were uniform in size distribution and had a good monodispersity. XRD results revealed that the Cu nanoparticles prepared by hydrothermal method were found to be good crystalline. The peaks showed in the picture corresponded to the formation of Cu (111), (200) and (220) nanocrystals. However, those prepared by ion-exchange method might be oxidized partially and displayed only a weak preferential (111) orientation. It was found by the fluorescence spectrophotometers that the copper ions displayed two emission band at 370 nm and 500 nm for the excitation at 270 nm. Meanwhile, the luminescence at 800 nm attributed to the excitation at 560 nm. UV-Vis absorption spectra indicated that the SPR peaks showed a red shift with increase of the ion-exchanged time and the reducing temperature.