Synthesis of ZnO ₂ nanoparticles by laser ablation in liquid and their annealing transformation into ZnO nanoparticles

A pulsed laser emitting UV radiations generated by the third harmonic of Nd:YAG was applied for the synthesis of nano-structured ZnO ₂ and ZnO. For the synthesis of nanoparticles of ZnO ₂ , a high-purity metallic plate of Zn target was fixed at the bottom of a glass cell, in the presence of deionized water mixed with oxidizing agent H ₂ O ₂ , under repeated laser irradiation. The optical properties, size and the morphology of the synthesized ZnO ₂ and ZnO by laser ablation was influenced strongly by post-annealing conditions which is not previously reported. By annealing ZnO ₂ at 200 °C for 8 h, the product (ZnO ₂ ) synthesized primarily was converted completely to ZnO. By variation of the annealing temperatures from 200 to 600 °C, the grain size of ZnO changes from 5 to 19 nm with a change in lattice parameters, the band gap and some other optical properties of nano-ZnO.