Thermal, optical and structural properties of Dy3+ doped sodium aluminophosphate glasses

• Sodium aluminophosphate glasses doped with Dy2O3 have been synthesised using melt quench technique.
• Field strength is enhanced with decrease in polaron radius and internuclear distance.
• Indirect optical band gap energy is attenuated due to augmentation of non-bridging oxygen atoms.
• Strong blue and yellow emissions are observed for Dy3+ ions in prepared glasses.
• PO4 tetrahedral units are distorted due to addition of modifiers like CaO, Na2O, Al2O3 and Dy2O3.

Trivalent Dysprosium doped sodium aluminophosphate glasses with composition 50P2O5-10Al2O3-(20-x)Na2O-20CaO-xDy2O3 (x varying from 0 to 5 mol%) were prepared by melt quench technique. The density of the prepared samples was measured using Archimedes principle and various physical properties like molar volume, rare earth ion concentration, polaron radius, inter nuclear distance and field strength were calculated using different formulae. The differential scanning calorimetry (DSC) was carried out to study the thermal stability of prepared glasses. The UV Visible absorption spectra of the dysprosium doped glasses were found to be comprised of ten absorption bands which correspond to transitions from ground state 6H15/2 to various excited states. The indirect optical band gap energy of the samples was calculated by Tauc’s plot and the optical energy was found to be attenuated with Dy3+ ions. The photoluminescence spectrum revealed that Dy3+ doped aluminophosphate glasses have strong emission bands in the visible region. A blue emission band centred at 486 nm, a bright yellow band centred at 575 nm and a weak red band centred at 668 nm were observed in the emission spectrum due to excitation at 352 nm wavelength. Both FTIR and Raman spectra assert slight structural changes induced in the host glass network with Dy3+ ions.

Variation of band gap energy and Urbach energy for prepared glass samples.Figure optionsDownload high-quality image (107 K)Download as PowerPoint slide