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

• Published in: Molecules
• Main Authors: Rajesh Dagupati, Robert Klement, Ramaraghavulu Rajavaram, José J. Velázquez, Dušan Galusek
• Format: Article
• Language: English
• Published: MDPI AG 2021-11-01
• Subjects: glass; glass-ceramic; optical thermometry; up-conversion; down-conversion
• Online Access: https://www.mdpi.com/1420-3049/26/22/6901
• ISSN: 1420-3049

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 (<i>S_r</i>) of 1.1% K⁻¹ at 298 K for TCLs in Er-G and Er-GC samples.