Self-assembled copt nanoparticles monolayer film and its IR optical properties

CoPt nanoparticles were prepared by galvanic displacement reaction, followed by a chemical reduction. The CoPt nanoparticles were spherical and the average diameter was about 33 nm obtained from the results of transmission electron microscopy (TEM), high resolution TEM and scanning electron microscopy (SEM). The results of powder X-ray diffration (XRD), energy dispersed X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) demonstrated that the surface of the product was mostly consist of Pt nanoparticles. An ordered monolayer film of CoPt nanoparticles on Si wafer was obtained by a Liquid/Liquid interface technique. In situ FTIR transmission spectral study indicates that the ordered self-assembled monolayer film of the CoPt nanoparticles shows Fano-like infrared effects, while the deposited CoPt nanoparticles exhibit normal enhanced IR adsorption. The results of the present paper demonstrated that the IR optical properties are closely related to the interactions and thickness of the nanomaterials and significant to understand the anomalous IR properties of nanometer materials.