Photoluminescent ZnO nanoparticles synthesized at the interface between air and triethylene glycol

ZnO nanoparticles with bright photoluminescence and different colors were synthesized through a very facile sol-gel method in triethylene glycol solvent at room temperature. Unexpectedly, the solvent molecules were found to be oxidized by air in the presence of LiOH and finally modified on ZnO nanoparticles. The molar ratio between LiOH and zinc acetate controlled the morphology and optical properties of the products. When LiOH was in excess, the as-prepared ZnO nanoparticles had a negatively-charged surface, which exhibited highly stable and blue fluorescence due to electrostatic repulsion between the particles.