Up‐conversion luminescence of Er3+/Yb3+ co‐doped Gd2Te6O15 tellurite glass‐ceramics for optical thermometry

Abstract

AbstractThe Er3+/Yb3+ co‐doped tellurite glasses and glass‐ceramics (GCs) containing the Gd2Te6O15 phase were successfully fabricated via the conventional melting‐quenching technique followed by a crystallization regime. The Er3+/Yb3+ co‐doped tellurite glasses generated intense up‐conversion green (524 and 546 nm) and red (658 nm) emissions when stimulated by a 980 nm laser. The up‐conversion green emission intensity increased by 68 and 46 times with the increase of the Yb3+/Er3+ ratio, and the optimal Yb3+/Er3+ ratio was found to be 8:1. The surface crystallization process of the Gd2Te6O15 GCs was confirmed through analysis of crystallization kinetics and microscopic morphology. The up‐conversion luminescence and lifetime of Er3+ ions were enhanced by the precipitation of low‐phonon‐energy Gd2Te6O15 crystals. The GC sample crystallized at 480°C for 4 h showed the highest luminescence intensity. The optical thermometry properties of Er3+ ions at thermally coupled energy levels (2H11/2/4S3/2→4I15/2) were explored. The Gd2Te6O15 GCs co‐doped with 0.25 mol% Er2O3 and 2.0 mol% Yb2O3 exhibited an excellent temperature relative sensitivity (Sr) of 1.22% K−1 at 293 K and a great repeatability of 98.07%. These results suggest that the Er3+/Yb3+ co‐doped Gd2Te6O15 GCs show promise for optical thermometry.