Influence of europium ion on structural, mechanical and luminescence behavior of tellurite nanoglass

Understanding the mechanism of enhanced luminescence of rare earth doped glasses in the presence of nanocrystallites and growth kineics is fundamentally important for optical devices. Tellurite nanoglasses of composition (80-x) TeO2 − 5 Na2O − 15 MgO − (x) Eu2O3, over the concentration region of 0 to 2.5 mol% are prepared using conventional melt-quenching technique. The nanocrystalline particles are obtained by heating the as-cast glass at temperature 15−20°C above the glass crystallization temperature (Tc). The sizes of nanocrystallites are estimated from the X-Ray Diffraction (XRD) pattern using the Scherrer equation having average diameter ~68.7 nm. SEM studies revealed the nanocrystal glass morphology associated with the existence of crystalline phase. The glass density is determined by Precisa Densitometer and the hardness by the Vickers micro-hardness method. The density of tellurite nano-glass is found to be in the range of 5.2413 to 5.4933 g cm−3 while the Vickers microhardness varies from 2.77 to 2.93 GPa depending on the dopant concentration. The photoluminescence (PL) spectra exhibits five peaks around 568 nm, 600 nm, 628 nm, 664 nm and 712 nm assigned to 5D0 → 7F0, 5D0 → 7F1, 5D0 → 7F2, 5D0 → 7F3 and 5D0 → 7F4 transitions respectively. Interestingly, the FWHM and the inverse quality factor of the heat-treated glass are found to decrease with increasing concentration of Eu3+ dopants. Our observation may contribute towards the development of solid state lasers