Study of linear and third-order nonlinear optical properties of TiO2/ZnO nanocomposite

In this study, structural characteristics and linear and nonlinear optical properties of TiO2/ZnO nanocomposite were investigated. In the first step, TiO2/ZnO composite nanostructure was prepared via a two-stage chemical coprecipitation approach by adding TiO2 nanoparticles into an aqueous solution containing zinc acetate precursor. In a second step, pure TiO2 and ZnO nanoparticles were synthesized by a co-precipitation method to investigate the presence portion of the basic structures on linear and nonlinear optical properties of TiO2/ZnO nanocomposite. Phase identification and chemical analysis of assynthesized nanostructures were performed by X-ray diffraction (XRD) crystallography and Fourier transform infrared (FT-IR) spectroscopy. Elemental properties of samples were studied by energy dispersive X-ray spectrometer (EDS) and surface mapping recorded by field emission scanning electron microscopy (FE-SEM). The morphological studies of the as-synthesized nanocomposite were analyzed by transmission electron microscopy (TEM). Linear optical studies were carried out to achieve the optical absorption edges and band-gap energies using UVVis spectra. Standard single-beam Z-scan technique with open-aperture (OA) and closed-aperture (CA) setups was utilized to determine nonlinear refraction index and nonlinear absorption coefficients, respectively. The optical nonlinear results showed a third-order optical susceptibility from the order of 10-4 esu under 532 nm laser radiations.