Optical Characteristics of Zinc Oxide Nanoparticles with Surface Modification Using Polyethylene Glycol

Surface of Zinc oxide(ZnO) nanoparticles prepared by Sol-Gel method was modified by a polymer reactant, PEG(polyethylene glycol, Mw=2000). The structure and optical properties of the PEG modified nanoparticles were then investigated by X-ray diffraction, Fourier transform infrared spectroscopy, photoluminescence spectroscopy, transmission electron microscopy. Results showed that the added PEG polymers were successfully coated on the surface of ZnO nanoparticles, without obvious variation being found in the ZnO crystal structure. The ZnO particles tend to have a smaller size, better stability and better dispersible uniformity after PEG coating. Furthermore, a defect state emission peak with significantly reduced intensity was found at the range of 400-500 nm in photoluminescence spectra, indicating that the surface defects of ZnO nanoparticles could be well improved by PEG modification.