Bridging between structure and optimum luminescence for nearly monodispersed Ce1−xGdxF3:Eu3+ nanoparticles

This work reports a systematic study on bridging between structure and optimum luminescence for Ce1−xGdxF3:Eu3+ nanoparticles. It is found that all Ce1−xGdxF3:Eu3+ nanoparticles were nearly monodispersed, showing average grain diameter of 30–35 nm. Regardless of the dopant level, all nanocrystals crystallized in a single hexagonal phase. With increasing Gd3+ content, the lattice dimension for Ce1−xGdxF3:Eu3+ linearly decreased, which was followed by the highly distorted lattice symmetry surrounding Eu3+. The consequence of the structural modification is that the color purity was significantly improved. Furthermore, the excitation energy of Ce3+ in the ultraviolet range was efficiently transferred to Eu3+ ions via the sensitizer Gd3+, which significantly enhanced the red emission and showed a maximized quantum efficiency of 59.7%.