Synthesis, microstructural and optical characterizations of sol-gel grown gadolinium doped cerium oxide ceramics.

In this study, through the utilization of the sol-gel combustion tactic, gadolinium (Gd)-doped cerium oxide (CeO 2 ), Ce 1- x Gd x O 2 ( x = 0.00, 0.10, 0.20 and 0.30 (GDC)) ceramics were attained. The synthesized GDC ceramics were investigated using X-ray diffraction (XRD) to scrutinize their crystal structures and phase clarities. The obtained GDC ceramics have a single-phase cubic structure and belong to the crystallographic space group fm 3̄ m (225). The measurement of the diffraction angle of each reflection and the subsequent smearing of the renowned Bragg's relation provided coarse d -interplanar spacings. The stacking fault (SF) values of pure and Gd-doped CeO 2 ceramics were assessed. To muse the degree of preferred orientation ( σ ) of crystallites along a crystal plane ( h k l ), the texture coefficient ( C i ) of each XRD peak of GDC ceramics is gauged. By determining the interplanar distance ( d h k l ), the Bravais theory sheds light on the material's development. By exploiting Miller indices for the prime (1 1 1) plane, the lattice constants of GDC ceramics and cell volumes were obtained. Multiple techniques were employed to ascertain the microstructural parameters of GDC ceramics. A pyrometer substantiated the density of GDC ceramics. The room temperature (RT) Fourier transform infrared (FTIR) spectra of both un-doped and Gd-doped CeO 2 were obtained. The UV-vis-NIR spectrometer recorded the GDC ceramics' reflectance ( R ) spectra at RT. For both undoped and Gd-doped CeO 2 , the absorption coefficient ( α ) spectra showed two distinct peaks. The R -dependent refractive index ( η ) and the α -dependent extinction coefficient ( k ) were determined for all GDC samples. The optical band gap ( E g ) was obtained by integrating the Tauc and Kubelka-Munk approaches for GDC ceramics. For each GDC sample, the imaginary ( ε i ) and real ( ε r ) dielectric constants, as well as the dissipation factor (tan  δ ), were determined local to the characteristic wavelength ( λ c ). Calculations were made for the Urbach energy ( E U ) and Urbach absorption coefficient ( α 0 ) for GDC ceramics. The minimum and maximum values of optical ( σ o ) and electrical ( σ e ) conductivity for GDC ceramics were determined. The volume (VELF) and surface (SELF) energy loss functions, which depend on the constants ε i and ε r , were used to measure electrons' energy loss rates as they travel across the surface. Raman spectroscopy revealed various vibrational modes in GDC ceramics. Finally, the implications are discussed herein.