Dielectric and optical properties of Ni- and Fe-doped CeO2 Nanoparticles

Ni- and Fe-doped CeO2 nanoparticles were prepared by a chemical co-precipitation method and then heat treated at 300 degrees C. The structural, morphological, and compositional properties of the prepared nanoparticles were studied by powder X-ray diffraction (XRD), Energy Dispersive Spectroscopy (EDS), Scanning Electron Microscopy (SEM) and Fourier-Transform Infrared (FT-IR) Spectroscopy. The powder XRD results revealed that all the samples exhibit the typical cubic fluorite structure of CeO2. The EDS and FTIR analyses confirmed the formation of CeO2 nanoparticles and the incorporation of Fe and Ni ions in the crystal lattice of CeO2. The photoluminescence (PL) properties were investigated to assess the effect of Fe- and Ni-doping on the emission properties of CeO2 nanoparticles. The impacts of the type of dopant on the dielectric properties and ac conductivity of the prepared nanoparticles were investigated. It was observed that the dielectric constant of Ni-doped CeO2 nanoparticles measured at low-frequency region is much greater than that of Fe-doped CeO2 nanoparticles. The difference was explained on the basis of interfacial/space charge polarization, with Ni-doped CeO2 nanoparticles having a more heterogeneous dielectric structure. The universal Jonscher power law was well adjusted to the ac conductivity spectra. It was shown that the Fe-CeO2 composite nanoparticles are less conductive than the Ni-doped CeO2 ones.