Europium-Doped Tellurite Glasses: The Eu2+ Emission in Tellurite, Adjusting Eu2+ and Eu3+ Emissions toward White Light Emission.

Hagar Elkholy,Hosam Othman,Dominique De Ligny,Ibrahim Hager,Medhat Ibrahim

doi:10.3390/ma12244140

Hagar Elkholy, Hosam Othman + Show 3 more

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https://doi.org/10.3390/ma12244140

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Abstract

Europium-doped magnesium tellurite glasses were prepared using melt quenching techniques and attenuated total reflection (ATR) spectroscopy was used to study the glass structure. The glass transition temperature increased with increasing MgO content. Eu2+ and Eu3+ emissions were studied using photoluminescence spectroscopy (PL). The broad emission of Eu2+ ions centered at approximately 485 nm was found to decrease in intensity with increasing MgO content, while the Eu3+ emission was enhanced. The Eu3+ emission lay within the red orange range and its decay time was found to increase with increasing MgO content. Different excitation wavelengths were used to adjust Eu2+ to Eu3+ emissions to reach white light emission. The white light emission was obtained for the sample with the lowest MgO content under excitation in the near-UV range.

Highlights

Tellurite glasses are known for their low phonon energy, ≤800 cm−1, much lower than borate, phosphate, and silicate glasses
The amorphous nature of the prepared Europium-doped magnesium tellurite glasses was confirmed by X-ray diffraction (XRD) measurement
We performed a thermal, structural, and spectroscopic analysis of binary magnesium tellurite glasses doped with 1 mol% of Eu2 O3

Summary

Introduction

Tellurite glasses are known for their low phonon energy, ≤800 cm−1 , much lower than borate, phosphate, and silicate glasses Beside their high liner refractive index (≈2), their nonlinear refractive index is high, making tellurite glasses excellent candidates for use in second- and third-generation harmonic applications [1,2]. Their overall high optical basicity (ˆth) will enhance the reduction of doped elements. Tellurite glasses are known for their low glass transition temperature (Tg ) and low melting (Tm ) temperatures They can be doped with high concentrations of rare-earth ions (REs), 50 times higher than silicate glasses, without presenting any quenching effect [3,4]. Two stable oxidation states of Europium were observed in glasses, namely, divalent and trivalent oxidation states [11,12,13]

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