Fluorescence enhancement of Ln3+ doped nanoparticles

Fluorescence emission of Ln3+ doped nanoparticles is influenced by many factors. Enhancement of fluorescence emission of Ln3+ doped nanoparticles can be achieved either through an external approach or an internal adjustment. The external approaches mainly include application of core/shell configuration and metal or semiconductor nanoparticles. Varying the crystal phase of the nanoparticle or introducing a codopant sensitizer are the internal approaches frequently used to obtain fluorescence enhancement, which are through inner adjustments to change the local structure, local symmetry and interaction with active ions. In the current work, efforts to obtain luminescence enhancement in Ln3+ doped nanoparticles through external or internal approaches are reviewed. The important roles of local symmetry and asymmetric interactions with optically active ions are extensively discussed.