Pure phase and europium-doped ceria nanocrystals have been synthesized by a single step simple solvothermal process. Different spectroscopic, diffractive, and microscopic techniques were used to determine the morphology, size, crystal
structure, and phase of all the samples. Electron energy loss spectroscopy (EELS) for elemental mapping confirmed that
good solid solutions were formed and that the particles had a homogeneous distribution of europium. The defect chemistry was more complex than might be expected with the incorporation of each Eu3+ ion resulting in the production of
an anion vacancy since the doping results in charge compensating (i.e., for Eu3+) anion vacancies as well as vacancies
due to oxygen removal from the crystallite surface. Variations in nanoparticles dimension and lattice parameters were measured as a function of dopant concentrations and their variations explained. The band gap of the samples could be tailored by the doping. The doped samples were found to be luminescent due to the substitution of Ce4+ ions in the cubic symmetric lattice by the dopant ions. The thermal stability of the fluorescence properties was also investigated.