Effect of alkali/mixed alkali metal ions on the thermal and spectral characteristics of Dy3+:B2O3-PbO-Al2O3-ZnO glasses

Thermal and spectroscopic features of 50 B2O3-10 PbO-10 Al2O3-10 ZnO-(x) Li2O-(y) Na2O-(z) K2O-1.0 Dy2O3 (mol %) (x = 19, y = 0, and z = 0; x = 0, y = 19, and z = 0; x = 0, y = 0, and z= 19; x = 9.5, y = 9.5, and z = 0; x = 9.5, y = 0, and z = 9.5; x = 0, y = 9.5, and z = 9.5) glasses, that were fabricated by utilizing melt quenching approach, are investigated by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), optical absorption, photoluminescence excitation (PLE), photoluminescence (PL), and PL decay lifetimes. PL spectra for all the Dy3+-doped samples show emission bands at 453 nm (blue), 482 nm (blue), 573 nm (yellow), 662 nm (red), and 752 nm (red) corresponding to the I-4(35/2) -> H-6(15/2) -> F-4(9/2) -> H-6(15/2), F-4(9/2) -> H-6(13/2), F-4(9/2) -> H-6(11/2), and F-4(9/2) -> (6)H(9/)2 transitions, respectively, upon excitation at 350 nm. Here, Dy3+: Li-Na glass shows the highest PL intensity for all identified emissions. The yellow-to-blue (Y/B) emission intensity ratio (varied within the range 1.257-L376), CIE chromaticity coordinates (x,y) (slight variation between (0.3410, 0.3802) and (0.3495, 0.3872), and correlated color temperatures (CCT5) (changed from 4953 K to 5212 K) are calculated following the PL spectra. Dy3+ F-4(9/2) decay curves show non-exponential behavior and are fitted by the Inokuti-Hirayama (I-H) model, where S = 6 shows best fit, indicating dipole-dipole (d-d) interactions for Dy3+ excited (donor) and ground state (acceptor) ions.