Luminescence of colloidal ZnO nanoparticles synthesized in alcohols and biological application of ZnO passivated by MgO.

This report presents the results of spectroscopic measurements of colloidal ZnO nanoparticles synthesized in various alcohols. Luminescence of colloidal ZnO was monitored, under different reaction condition, to elucidate the mechanism of the visible emission. We perform the process in different alcohols, temperatures and reaction time for two different reactants: water and NaOH. Based on the presented and previously published results it is apparent that the luminescence of the nanoparticles is influenced by several competing phenomena: the formation of new nucleation centers, the growth of the nanoparticles and surface passivation. Superimposed on the above effects is a size dependent luminescence alterations resulted from the quantum confinement. The study contributes to understanding the origin of ZnO nanoparticles green emission which is important in a rational design of fluorescent probes for nontoxic biological applications. Thus produced nanoparticles are coated with a magnesium oxide layer, and introduced into the HeLa cancer cell