Enhancing structural, optical and dielectric properties of CuO–ZnO nanocomposites through controlled CuO and ZnO concentration adjustments

Abstract

This study employed sol–gel technique to synthesize CuO_x-ZnO_1-x nanocomposites with varying concentrations of CuO (x = 0, 0.25, 0.50, 0.75 and 1.00). The resulting samples were analysed using X-ray diffraction (XRD) to confirm the presence of hexagonal wurtzite ZnO and monoclinic CuO phases. Scherrer’s formula and W–H plot were used to determine crystallite size and microstrain, revealing a reduction in crystallite size from 37 to 23 nm with increasing CuO concentration. Optical analysis showed a visible spectrum absorbance and a decreasing optical band gap from 3.25 to 1.54 eV with higher CuO concentrations, impacting photovoltaic and optoelectronic applications. Dielectric studies demonstrated Maxwell–Wagner interfacial polarization across a frequency range (100 Hz–1 MHz) and temperatures (303–573 K), while AC conductivity exhibited low-frequency dispersion revealing enhanced properties with CuO addition. Overall, this study provides valuable insights into CuO-induced modifications in ZnO nanostructures, informing the design of materials with enhanced optical and electrical properties for advanced optoelectronic technologies.