Synthesis of ZnO nanostructures and its effect on linear-nonlinear optical properties

Abstract

Zinc oxide (ZnO) nanostructures with nanoparticle morphology have been synthesized at ambient pressure and different temperatures using [OMIM]Br ionic liquid as solvent by ionothermal method. The products were characterized by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and Z-scan technique. The average crystallite size of ZnO was between 15-23 nm. The band gaps of products are 3.19, 3.25, and 3.32 at 65, 90, and 120 oC, respectively. The Z-scan technique was proposed to detect the nonlinear optical (NLO) properties at 532 nm wavelength. Temperature effect on third order NLO responses of ZnO nanostructures is studied. The results show that higher annealing temperature in ionic liquid produced ZnO nanoparticles with decreased crystalline and enlarged band gap. Also, this process leads to produce ZnO nanoparticles with increasing NLO responses by altering vacancy distribution.