Improvement of Optical Properties of Functionalized Polyvinyl Alcohol-Zinc Oxide Hybrid Nanocomposites for Wide UV Optoelectronic Applications

Abstract

The functionalized polyvinyl alcohol (PVA) based nanocomposites thick films of 80 μm containing 1–3 wt% zinc oxide (ZnO) nanoparticles (NPs) were studied. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and Raman spectroscopy were utilized for studying the structural parameters and formed chemical bonds of the synthesized PVA-ZnO films. In addition, extensive characterization has been done on their linear and nonlinear optical properties. The structural analysis of the PVA-ZnO nanocomposites revealed the formation of a wurtzite hexagonal ZnO phase embedded inside the monoclinic PVA phase. The interaction between Zn–O, and functional groups of the PVA as well as the molecular vibration exhibited in the PVA-ZnO nanocomposites were confirmed by the Raman and FTIR spectroscopy and revealed that the PVA-ZnO is a hybrid nanocomposite. The incorporated ZnO NPs ratios slightly affect the PVA films' structure, meanwhile, exhibited a detectable change in the linear/nonlinear optical properties of PVA. For example, as ZnO concentration increased from 1 wt% to 3 wt%, the direct/indirect optical band gap of PVA slightly decreased from 5.1/4.93 eV to 4.45/4.89 eV, respectively. Other optical characteristics, such as optical conductivity, dielectric constants, absorption coefficient, refractive index, etc., were evaluated. All observed optical properties versus energy/wavelength display a distinct pulse at 1.4 eV/850 nm which corresponds to the difference between the direct and indirect optical band gaps. It is expected that PVA-ZnO hybrid nanocomposites have become appropriate for implementation in numerous electronic applications due to their improved optical characteristics.