Abstract
A series of copper nanocrystals with various sizes was prepared by using the extract of portulaca oleracea leaf as an efficient reducing agent and hydrolyzed polyvinyl alcohol as stabilizing agent. The X-ray diffractions disclose cubic structure of these copper nanoparticles. The TEM measurements inspected the monodispersion of the Cu nanoparticles and the increase of their diameters from 2.4 nm to 8.3 nm. The HRTEM inspected the tendency of the Cu nanoparticles to grow along (111) planes. The optical absorption spectra revealed a strong absorption spectrum in the visible region, which argued to the localized surface plasmon resonance. The resonance plasma frequency is exponentialy decreases with the increase of the size of Cu nanoparticles. The luminescence spectrum displaced from 603 nm to 654 nm because of the increasing of Cu size. The scattered wavelengths from the surface of copper nanocrystals exhibited fabulous emitted colors. These unique features may enable the prepared copper nanocrystals with various sizes to be employed for optical remote sensing, optical filters, waveguides and transmitting antenna applications.