Effect of Lithium and Sodium ions on size and morphology of ZnO nanoparticles synthesized by glycerol-urea route

ZnO nanoparticles having spherical and rod shapes with high crystallinity and uniform average crystallite sizes were prepared by the glycerol-urea route (GU). The syntheses were carried out using Zn(NOtext-decoration:underline'3)text-decoration:underline'2.6Htext-decoration:underline'2O and NaOH in a 3:1 mol ratio of G:U solution under stirring at 70 °C. These reactions took less than 1 hour to completion with a high mass yield. NaCl and LiCl salts were added to attempt to modulate crystallites morphology and size. The effect of LiCl led to smaller spherical particles with an average size of 11(2) nm, whereas NaCl resulted in rod-shaped ZnO nanoparticles with an average length of 44(7) nm and average diameter of 12(2) nm; whereas GU synthesis (no salt) led to 19(3) nm nanoparticles. A detailed X-ray powder diffraction, FT-IR and UV-vis analyses confirmed the typical wurtzite structure of the particles. Electron microscopy images (SEM and TEM) showed the morphology and size of the ZnO. Photoluminescence revealed different behavior related to defects and exciton emission.