The influence of ZrO2 addition on the morphological, structural, vibrational, and optical characteristics of composite fibers based on ZnO

Abstract

In this work, pure ZnO and ZrO2 /ZnO composite fibers with different molar ratios (1: 3, 1: 1, 3: 1) were fabricated from homogeneously mixed zinc acetate, zirconium oxychloride and polyvinylpyrrolidone solution by electrospinning technique followed by heat treatment at 500 °C. The effects of ZrO2 concentration on the morphological, vibrational, structural, and optical features of the samples were investigated by diverse analyses. The beads-free and smooth structure of the composite nanofibers were examined by scanning electron microscopy. The crystallization of ZnO wurtzite and tetragonal ZrO2 structures were demonstrated using the Zn-O and Zr-O stretching vibrations in the Fourier transform infrared spectra and X-ray diffraction patterns. Also, the influence of ZrO2 concentration on the microstructure parameters of nanostructured samples was determined by the whole powder pattern modeling mean. The diffuse reflectance and photoluminescence spectroscopies were applied to investigate the optical properties of samples. The band gap value was estimated from the first derivative of the absorbance data with respect to the photon energy. The blue emissions (400–460 nm) in photoluminescence spectra were caused by defects like Zn interstitial/vacancy, Zr interstitial/vacancy, and O interstitial/vacancy. The characteristic blue emission shoulder at 2.59 eV may be raised of the electron transition from Zn interstitial to Zn vacancy.