Characterization of Nd3+-doped Tellurite Glasses with Low OH Content

Francine Bettio Costa,João Carlos Silos Moraes,Sandro Marcio Lima,Keizo Yukimitu,Luis Humberto Da Cunha Andrade,Luiz Antonio Oliveira Nunes

doi:10.1590/1516-1439.320614

Francine Bettio Costa, João Carlos Silos Moraes + Show 4 more

Open Access

https://doi.org/10.1590/1516-1439.320614

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Abstract

This work presents the results of the investigation of structural and thermal properties of Nd3+-doped tellurite glasses with low OH content. The samples were characterized by XRD, FTIR, DTA, UV/VIS/NIR and Archimedes’ method. Tellurite glasses of composition (100 – x)(0.8TeO2 + 0.2WO3) + xNd2O3 (x = 0, 0.05, 0.5, 1, 2, and 4 mol%) were prepared in both ambient and oxygen atmospheres. All samples showed an increase of the values of Tg, Tx, and Tx-Tg with Nd2O3 addition. The reduction of OH content implies a slight decrease of Tg. The density and the molar volume of the glasses increased with Nd2O3. The intensity of the absorption bands associated with Te-O bonds of TeO4 units decreased compared with the bands associated with Te-O bonds of TeO3+1/3 units. This indicates that Nd2O3 favors the transformation of the TeO4 groups in TeO3 groups via TeO3+1, increasing the NBOs and contributing to the formation of strongly hydrogen-bonded OH groups. The samples made in O2 showed a reduction of 48% of “free” OH ions compared with the Amb ones.

Highlights

Tellurite glasses combine the attributes of reasonable thermal stability, high refractive index, high solubility of rare earth (RE) ions, larger absorption and emission cross‐sections, and low phonon energy compared to the silicate, phosphate, and borate glasses[1,2], with a wide transmission window in the infrared region[2]
The absorption spectra were recorded in the range of 400 to 1000 cm–1 for the powder samples and in the range of 2000 to 4000 cm–1 for the bulk samples using an N2 purge, and were obtained by Fourier transform infrared (FTIR) spectroscopy using a Nicolet Nexus 670 FTIR spectrometer
The X-ray diffraction (XRD) curves of the undoped and Nd3+-doped TW glasses prepared in both atmospheres presented two halos that confirm the amorphous nature of the glasses

Summary

Introduction

Tellurite glasses combine the attributes of reasonable thermal stability, high refractive index, high solubility of rare earth (RE) ions, larger absorption and emission cross‐sections, and low phonon energy compared to the silicate, phosphate, and borate glasses[1,2], with a wide transmission window in the infrared region[2]. The RE-doped tungsten-tellurite glasses have been shown to have excellent properties for applications such as planar waveguides[4], amplifiers[5], and lasers[6,7]. Nd3+ ion is one of the most investigated This is due to the high quantum efficiency of the. The absorption losses due to the OH groups are disadvantageous because they decrease luminescence quantum efficiency, hindering the practical use of these glasses[11,12,13]. We investigate the thermal and structural properties of the Nd3+-doped tungsten-tellurite glasses

Experimental

Results and Discussion

Conclusions