In Situ Synthesis of β-Na1.5Y1.5F6: Er3+ Crystals in Oxyfluoride Silicate Glass for Temperature Sensors and Their Spectral Conversion and Optical Thermometry Analysis

Abstract

Transparent oxyfluoride glass-ceramics (GCs) with embedded β-Na1.5Y1.5F6 crystals doped with Er3+ ions were fabricated by a melt-quenching method with subsequent heat-treatment. The structural characterizations and spectroscopic techniques were performed to verify the precipitation of β-Na1.5Y1.5F6 crystals and partition of the Er3+ dopant into the crystals. Bright green up-conversion (UC) emission was achieved in Er3+-doped glass-ceramic (Er-GC). Furthermore, the temperature-dependent visible UC behavior based on thermally coupled energy levels (TCLs) and non-thermally coupled energy levels (NTCLs) was also examined in the temperature range 298 k to 823 K with maximum relative sensitivity (Sr) of 1.1% K−1 at 298 K for TCLs in Er-G and Er-GC samples.

The influence of Al2O3 concentration on the NaYF4 crystallization in oxyfluoride glass–ceramics

“…The power‐dependent UC spectra for 5Al_Er_GC and 10Al_Er_GC are shown in Figure 13A,B, respectively, after excitation at 980 nm. The UC intensity ( I UC ) increases with increasing pump power ( P ) and follows the relation I UC ∝ P n , 41 where n is the number of photons required to achieve UC transitions. The double logarithmic plot of the UC transition intensity against pump power is shown in Figure 13C,D.…”