Oxygen vacancies and defects tailored microstructural, optical and electrochemical properties of Gd doped CeO2 nanocrystalline thin films

In this study, the authors present a pure and Gadolinium (Gd) doped CeO2 nanostructures, successfully elaborated onto the glass and Indium Tin Oxide (ITO) coated glass substrates under optimized parameters. A spray pyrolysis method was used at a temperature of 450 C, with simultaneous incorporation of Gd at various concentrations (0, 2, 4, 6, 8 at. %) as a dopant. Different techniques for characterization were used to study the Gd impact on the microstructural, the morphological, the optical and the electrochemical behaviors of the CeO2 material. The XRD patterns shows that Gd3+ ions are inserted at the Ce4+ ion sites in the cubic fluorite structure network of CeO2 nanocrystals (NCs). Raman spectroscopy and UV-Vis-NIR have been utilized to study the defect structure and optical behaviors in these NCs. Broadening and Peak asymmetry of Raman active mode are attributed to the existence of Ce3+ and oxygen vacancy, which have been changed with addition of Gd3+ ions in CeO2 NCs. The results of UV-Vis-NIR spectroscopy show the variations of the optical gap energy with fluencies of Gd3+ due to the variations of particles sizes of NCs. Cyclic voltammetry results show that the ion storage capacities (ISC) of CeO2 thin films are increased with Gd doping. This research paper reports on the fluencies of Gd doping in CeO2 nanocrystals, to understand the role of oxygen vacancies and the impact they have on the tailoring of the microstructural, optical and electrochemical behaviors of doped CeO2 nanocrystals for multiple applications such as, catalysts, oxygen transportation, ultraviolet fuel cells, and electrochromic devices etc.