Novel transparent Tb3+-activated Na2GdF7 glass ceramics for low-lying state thermal coupling principle

Abstract

Oxy-fluoride glass ceramics (GC), which are composed of glass phase and equally distributed fluoride nano-crystals, are regarded as promising host materials employed to optical thermometer. Herein, novel Na2GdF7:xTb3+ (x = 0.02, 0.03, 0.04, 0.05, and 0.06) GC with high transparency were well fabricated and applied to low-lying state thermal coupling principle. The structural, micro-topography and fluorescence spectra properties of these samples were completely researched via XRD, TEM, HRTEM, SAED and photoluminescence. When excited by 378 nm laser, the luminescence of Na2GdF7:0.3Tb3+ GC was increased 1.5 times compared with precursor glass. More importantly, the Na2GdF7:0.3Tb3+ GC sample (λex = 541.8 nm) was devoted to low-lying state thermal coupling principle. The strategy endows excellent relative sensitivity and superior temperature resolution which are 2.33% K−1 at 310 K and 0.06 K at 670 K, respectively. These findings suggest potential optical materials and a strategy for optical fiber temperature sensing.