Synthesis of Fluoride Nanoparticles in Non‐Aqueous Nanoreactors. Luminescence Study of Eu³⁺:CaF₂

Monodispersed CaF 2 and Eu 3+ :CaF 2 nanoparticles were synthesized through an original non‐aqueous route involving isopropanol nanoreactors dispersed in a polystyrene / THF solution. Transmission electron microscopy revealed a mean diameter of 15 nm with a small standard deviation of 5 nm, for both, undoped and doped nanoparticles. CaF 2 particles exhibit a cubic morphology, while Eu 3+ :CaF 2 particles are rather spherical. Luminescence experiments carried on Ca 1−x Eu x F 2+x (x = 0.1) at room temperature, revealed that europium cations are only located in one type of site in the CaF 2 structure, with an environment rather constituted by F − anions than by OH − or O 2− , showing the absence of these later in the synthesized nanoparticles. These measurements highlighted also a long mean life‐time for the 5 D 0 state of trivalent europium (5.6 ms), compared to the ones observed in literature (around 3 ms). By an adequate choice of reagents, this waterless method of preparation could be adapted allowing the synthesis of other water sensitive compounds than fluorides.