Lithium-boron-aluminum glasses and glass-ceramics doped with Eu3+: A potential optical thermometer for operation over a wide range of temperatures with uniform sensitivity

• Published in: Journal of alloys and compounds Vol. 907; p. 164402
• Main Authors: Laia, André S., Maciel, Glauco S., Rodrigues, José J., Dos Santos, Marcos A.C., Machado, Rogerio, Dantas, Noelio O., Silva, Aniele C.A., Rodrigues, Rafael B., Alencar, Márcio A.R.C.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 25-06-2022; Elsevier BV
• Subjects: Aluminum; Asymmetry; Boron; Crystal growth; Emission analysis; Emission spectra; Europium; Glass ceramics; Heat; Heat treatment; Lithium; Luminescence; Optical thermometry; Parameters; Rare-earth; Sensitivity; Spectrum analysis; Temperature; Temperature sensors; Thermometers; Thermometry; Optical thermometry; Rare-earth; Luminescence; Glass-Ceramics
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2022.164402

•Eu-doped Li2O - B2O3−Al2O3 glasses and glass ceramic were synthesized.•The calculated Judd-Ofelt intensity parameters of these media were ~ 10−20 cm−1.•The glass ceramic showed greater emission intensity than the precursor glass.•They are efficient probes for optical thermometry using peak-valley ratio method.•Nearly constant relative sensitivity was obtained over a wide temperature range.
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In this work, lithium-boron-aluminum (LBA) glasses doped with Eu3+ were produced by the traditional melting method. These precursor glasses (PG) were heat treated at 400 and 450 °C for 6 h to produce glass-ceramics (GC). The X-ray diffraction measurements showed the formation of a crystalline phase. In the LBA GCs, crystal growth is nucleated at the surface and an increase in the emission intensity of the heat-treated glasses compared with the PG was observed. Spectral analysis of the luminescence indicated that Eu3+ occupies low-symmetry site (asymmetry ratio ≈ 4) and without an inversion center. The emission spectra were analyzed using Judd-Ofelt theory and the intensity parameters Ω2, Ω4 and Ω6 were calculated. The values of these parameters were not significantly affected by the heat treatment process. The application of these materials as optical temperature sensors using the valley-peak intensity ratio (VPIR) was investigated using the multi-peak spectral profile of the 5D0 → 7FJ luminescence bands of Eu3+. We estimated the relative sensitivity, the figure-of-merit of the thermometer, to be as high as 0.40 ± 0.02% K−1. Interestingly, some VPIR that were explored presented a constant value for the relative sensitivity across the temperature interval used in our experiment (between 312 and 393 K), which is advantageous for sensor operation over a broad temperature range.