Tunable fluorescence and magnetic properties of ceria- organic core- shell hollow structures

Abstract

In this study, mesoscopic ceria- organic core–shell hollow spheres with tunable luminescence and magnetism were demonstrated. The organic layer was grown on the surface of ceria hollow spheres by the reaction of citric acid solution and ethylenediamine via hydrothermal process. With increasing the reaction time from 0 to 6 h, the organic phase varies from discontinuous carbon- rich dots to a nanometrical layer which contains randomly distributed Ce3+- rich clusters. The growth process of the surface organic phase accelerates the formation of defect layers on the surface of ceria hollow spheres, while inhibiting further reduction inside the ceria shell. The synergistic effect formed by the structural changes of the surface organic phase and underlying ceria enables all samples to exhibit ferromagnetic and luminescent properties at room temperature. The ferromagnetic strength closely depends on the continuity and defect content of the Ce3+-rich layer on the surface of the ceria hollow spheres. The enhanced fluorescence, especially the blue and red emissions, is attributed to the defective structure of ceria and the composition of the organic phase.