Monodispersing Eu3+ and Li+ codoped CaF2 nanoparticles for efficient luminescence

Monodisperse oleic acid (OA) modified Eu 3+ and Li + codoped CaF 2 nanoparticles are presented in this work. The as-obtained nanoparticles, with a hexagonal shape, can be well-dispersed in organic apolar solvents. The incorporation of Li + ions in CaF 2 :Eu 3+ does not lead to new crystalline phases. The main diffraction peaks are found to shift to small angles when codoped with 7 mol% Li + , while a reverse shift can be noted with the codoping amount increasing to 9 mol% Li + , indicating that the codoped Li + enables the crystal field environment of Eu 3+ to be changed. The excitation and luminescence intensities of all peaks indexed to Eu 3+ have enhanced apparently when codoped with 7 mol% Li + ions. The lifetime of the 5 D 0 state of Eu 3+ ions is also increased by introducing 7 mol% of Li + ions.