Abstract
We investigate the effects of laser irradiation on the optical properties of ZnO nanoparticles in an organic solvent. ZnO nanoparticles are synthesized using normal precipitation methods in 2-propanol. Irradiating the nanoparticles in the solvent with unreacted reactants, which is colloidal solution without purification after the preparation, results in a reduction in the green luminescence, which is related to the number of surface oxygen defects, and an increase in the ultraviolet luminescence, which is related to the crystallinity of ZnO. Irradiation does not, however, significantly alter the nanoparticle diameter. Conversely, irradiation of purified (reactant-free) ZnO nanoparticles in the solvent does not change the ZnO photoluminescence intensity. We conclude that laser irradiation of the ZnO nanoparticles dispesed with reactants reduces the number of surface defects on the ZnO nanoparticles. Without the reactants, laser irradiation of the ZnO nanoparticles in the solvent does not modify the surface defects concentration, nor does it increase the crystallinity.