151Eu Mössbauer study of luminescent Y2O3:Eu3 + core-shell nanoparticles

151Eu Mossbauer spectroscopy was applied to distinguish among different Eu microenvironments and phases in spherical Y2O3:Eu3 + and core-shell Y2O3@Eu3 + phosphor nanoparticles prepared by using homogeneous precipitation method. 151Eu isomer shift revealed that Eu atoms exist only in oxidation state Eu3 + in all spherical and core-shell phosphors. Significant differences have been found between the Mossbauer parameters (isomer shift, principal component of EFG and linewidth) characteristic of spherical Y2O3:Eu3 + and core-shell Y2O3@Eu3 + phosphor nanoparticles. The Mossbauer parameters of spherical Y2O3:Eu3 + were associated with Eu substituting Y in the Y2O3, while Mossbauer parameters of core-shell Y2O3@Eu3 + phosphor were attributed to Eu being in the Eu2O3 shell, proving the structural model and the successful preparation of these phosphors.