Fluorescent Enhancement of CaF 2 : Nd 3+ Nanoparticles through a Concentration‐Gradient Core/Shell Hybrid Structure

In this contribution, we provided an efficient core/shell structure for CaF2 : Nd3+ based core/shell NPs, which has several traits below: hybrid core; homogeneous or heterogeneous core-host and shell-host; concentration-gradient distribution of both doping ions and activator from inner to outer shell layer. Finally, A successive layer-by-layer doping method was utilized to synthesize various core-based and concentration-gradient hybrid Ce3+, Li+ and activator (Nd3+) shell layer core/shell(C/S) NPs, which could enhance the fluorescence of the CaF2 : 6Nd(mol %) C/S NPs up to 21.4 times than that of core-only NPs by doping much denser hybrid Ce3+ and activator Nd3+ in per unit volume and overcoming surface quenching.