Tuning Photophysical Properties of ZnO/TiO2 Nanocomposite Thin Films by Controlling Anatase Titania Content

Abstract

The influence of the anatase titania nanoparticles (TiO2 NPs) content on the structural and optical properties of ZnO/TiO2 nanocomposites (ZTNCs) was demonstrated. The solution blending method was employed to prepare the ZTNCs with various ratios prior to their deposition onto glass substrates to form thin films. The X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), and transmission electron microscope (TEM) techniques revealed that the crystallite size, grain size, and particle size of each TiO2 and ZnO NPs are almost equal. In addition to these techniques, Fourier transform infrared spectroscopy (FTIR) evidenced the homogeneity distribution of the TiO2 within the ZnO NPs. The structural properties of the wurtzite ZnO NPs such as crystallite size, lattice strain, dislocation density, bond length (L) of Zn–O, energy density (u), lattice stress (L S), Young’s modulus, and unit cell volume (V), can be tuned by incorporation of anatase TiO2 NPs in various content. Moreover, the optical properties of the wurtzite ZnO NPs such as absorbance, optical energy band gap (E g), energy gap tail (E u), steepness parameter (σ), and emission intensity can be tuned by incorporation of anatase TiO2 NPs in various contents. The E g and σ of ZnO NPs were decreased to reach at 2.41 eV and 0.0051, respectively, whereas the E u was increased to 4.598 eV upon the increment content of TiO2 NPs.