Highly doped alkaline earth nanofluorides synthesized from ionic liquids

Bulk alkaline earth fluorides co-doped with optically active ions are prominent materials for luminescent applications. However, for phosphor materials the changeover to the nanoscale is a tightrope walk between achieving desirable features of small particles such as reduced light scattering and unwanted drawbacks such as a high surface defect concentration which is likely to result in quenching of luminescence. A new preparation route via ionic liquids allows obtaining pure and oxygen-free alkaline earth fluorides co-doped with Eu3+ and Gd3+ on the nanoscale with excellent quantum cutting abilities.

► New synthetic route to pure alkaline earth nanofluorides with excellent luminescent properties via ionic liquids. ► High degree of optically active ion doping whilst maintaining the cubic structure. ► Alkaline earth fluorides show dependence of Gd3+ concentration on particle size, lattice strain, quantum cutting. ► Quantum cutting efficiencies up to 190 %.