Colour-tunable features in thermally stable Tb³⁺/Eu³⁺ co-doped telluro tungstate glasses for photonic applications

Abstract

The melt quenching procedure has been followed to synthesize transparent Tb3+ singly activated and Tb3+/Eu3+ co-activated TeO2 –WO¬3 – K¬¬2O – ZnO – Bi2O3 (TWKZBi) glasses. The structural characteristics of the prepared TWKZBi glass samples were examined through X-ray diffraction (XRD). The existence of functional units corresponding to the different vibrations has been examined via Raman spectroscopy. The photoluminescent (PL) characteristics and energy transfer (ET) analysis in the Tb3+/Eu3+ co-activated TWKZBi glasses were investigated in depth. Several emission peaks have been observed in Tb3+ doped TWKZBi glasses under n-UV and blue excitations and the maximum luminescent intensity has been detected for 2.0 mol% of Tb3+ doped TWKZBi glass sample. The emission spectra of co-doped Tb3+ and Eu3+ ions in the TWKZBi glasses have been studied, and the maximum energy transfer efficiency is found to be 32.82% under n-UV excitation. The ET from sensitizer (Tb3+) to activator (Eu3+) ions happen through dipole-dipole (d-d) interaction, as confirmed by Dexter’s and Reisfeld’s approximation. The color-tunable emission in the prepared glass samples can be achieved via varying the content of activator ions. The decay profiles for the 5D4 level of Tb3+ ions diminish with varying the concentration of Eu3+ ions, confirming the energy transfer from Tb3+ to Eu3+ ions. Furthermore, temperature-dependent photoluminescence (TDPL) studies show that the Tb3+/Eu3+ co-doped TWKZBi glasses have good thermal stability. All the aforementioned results reveal the suitability of the Tb3+/Eu3+ co-activated TWKZBi glass samples for photonic applications.