Energy Cluster in Fluoride Glass Enabling Enhanced Upconversion Toward Fluorescent Thermometry

Fluoride glasses, with low phonon energy and high rare-earth ions solubility, show great promise for UC fluorescence thermometry. However, the trade-off between the enhanced luminescence intensity and poor thermal stability through heavy doping limits their application.

In this study, based on structural design, we adopted an isostructural substitution doping strategy to provide a solution for the preparation of thermally stable, highly rare-earth-doped fluoride glass. Furthermore, an energy cluster structure was constructed within the glass phase, achieving a high quenching concentration and enhanced UC luminescence. The resulting ZBEA glass achieved a doping concentration of 9 mol% and exhibited a 350-fold enhancement in blue multiphoton UC emission intensity.