Green Synthesis of A2 SiF6 (A=Li-Cs) Nanoparticles using Ionic Liquids as Solvents and as Fluorine Sources: A Simple Approach without HF.

In this Communication, nanoparticles of the fluoridosilicates A2 SiF6 (A=Li, Na, K, Rb, Cs), which are extremely promising host lattices for future LEDs, are presented for the first time. The preparation method we introduce here is a very simple and energy and time saving one, moreover the usage of toxic HF or elemental fluorine is avoided. In detail, the ionic liquid [Bmim]PF6 was used both as solvent and fluoride source in an ionothermally assisted microwave synthesis. The small size of the so-obtained nanoparticles is of huge relevance for their applications as thin films or for the coverage of surfaces, for example in next-generation white LEDs upon doping with Mn4+ .