Na2O doped CeO2 and their structural, optical, conducting and dielectric properties

Highlights: • All the samples are synthesized by solid state reaction method. • The dielectric constant decreased after addition of Na₂O in CeO₂ based samples. • Charge difference between Na²⁺ and Ce⁴⁺ is not enhancing the conductivity of the base material. • Low concentration of the dopant exhibits the highest conductivity with the lowest relaxation time. - Abstract: In the present study, Na₂O doped CeO₂ has been prepared by solid state reaction method. The prepared samples are characterized by X-ray diffraction (XRD), UV–Visible spectroscopy, Fourier transform infrared (FTIR) spectroscopy, Scanning electron microscope (SEM) and Impedance spectroscopy. The optical band gap of all the samples lies in the semiconducting range i.e. 3.04–3.25 eV. The highest optical band gap is observed for 5 mol% Na₂O doped CeO₂. The SEM images show a non-uniform distribution of particles with an average particle size of ∼3.15 μm for all the samples. The lowest dielectric constant is observed to be ∼11 at 100 °C and 100 Hz for 10 mol% doped CeO₂ which is lower than the undoped CeO₂. The conductivity of the samples lies in the range of 10⁻⁷ S/cm at 700 °C.