Novel and easy access to highly luminescent Eu and Tb doped ultra-small CaF2, SrF2 and BaF2 nanoparticles – structure and luminescence

• DOI: 10.1039/c6dt04711d
• Publication Date: 2017-01-31T08:54:21Z
• Authors: Benjamin Ritter; Philipp Haida; Friedrich Fink; Thoralf Krahl; Kornelia Gawlitza; Knut Rurack; Gudrun Scholz; Erhard Kemnitz
• Keywords: Dispersity; Quantum yield

A universal fast and easy access at room temperature to transparent sols of nanoscopic Eu3+ Tb3+ doped CaF2, SrF2 BaF2 particles via the fluorolytic sol-gel synthesis route is presented. Monodisperse quasi-spherical nanoparticles with sizes 3-20 nm are obtained up 40% rare earth doping showing red or green luminescence. In beginning luminescence quenching effects only observed for highest content, which demonstrates unique outstanding properties these materials. From CaF2:Eu10 SrF2:Eu10 BaF2:Eu10 a steady increase intensity lifetime occurs by factor ≈2; photoluminescence quantum yield increases 29 35% due lower phonon energy matrix. The formation process within fractions seconds clearly visualized exploiting appropriate processes during synthesis. Multiply also available this method. Fine tuning achieved variation Ca-to-Sr ratio. Co-doping Ce3+ results in huge (>50 times) transfer → Tb3+. case, higher CaF2 than SrF2, spatial distance ions.