Ionic liquid/H2O two-phase synthesis and luminescence properties of BaGdF5:RE3+ (RE = Ce/Dy/Eu/Yb/Er) octahedra

Abstract

Rare earth doped BaGdF₅ compounds have received much attention because they not only exhibit excellent upconversion emission, but also present attractive paramagnetic properties derived from the large magnetic moment of Gd³⁺ ions. Although great efforts have been made to realize the controllable synthesis of BaGdF₅ nano- or micro-crystals, more environmentally friendly solvents and reactants rather than organic solvents and trifluoroacetates were expected to be used. In this work, we have reported an ionic liquid/H₂O two-phase system to synthesize Ce³⁺/Dy³⁺/Eu³⁺/Yb/Er doped BaGdF₅ octahedra, in which an environmentally friendly ionic liquid was used as the reactant and morphology controller. The growth mechanism of BaGdF₅ octahedra has been proposed. Furthermore, the luminescent color of BaGdF₅:Ce³⁺/Dy³⁺/Eu³⁺ octahedra can be tuned by adjusting the doping concentration of Ce³⁺, Dy³⁺, and Eu³⁺ ions. In addition, the up-conversion emission related temperature sensing performance of BaGdF₅:Yb/Er has been discussed and this phosphor showed potential application in thermal sensing. This work provides a new route for the synthesis of rare earth fluorides.