Abstract:

In the present work, we prepared two kinds of quantum-sized wurtzite ZnO particles whose average sizes were about 3 nm and 5 nm, respectively. The particles prepared were characterized by UV-Vis absorption spectra, IR spectra, XRD, TGA, DTA, transmission electron microscopy (TEM), surface photovoltage spectra (SPS) and electrical field induced surface photovoltage spectra (EFISPS) etc.. IR study showed that acetic acid molecules coordinated to the surface of ZnO in two modes, one is of the bridging type, and the other of the unidentate type. The latter is weaker. It was indicated by EFISPS that the two kinds of particles have very different surface properties because of their different sizes and preparation processes. We found that basic zinc acetate structure exists on the surface of 3 nm particles. While for 5 nm particles prepared by aging the 3 nm particles, that surface structure disappeared, but the particles were doped with lithium ions in the aging process. The above phenomena were explained by considering the hydrolytic chemistry of zinc acetate.

Key words: Zinc oxide, Nanoparticles, Preparation, Surface properties