Effect of Dy3+ on the physical, optical and radiative properties of CaSO4–B2O3–P2O5 glasses

Abstract

The unprecedented attributes of the trivalent rare earth ions-doped sulfoborophosphate glasses have led to tremendous interest in exploring their potentials for application in diverse photonic devices. Calcium sulfoborophosphate glasses doped with dysprosium ions were prepared by a melt-quenching technique with varying concentrations of Dy3+ that range from 0.1 to 1.0 mol%. Amorphous nature of the prepared glasses was determined using X-ray diffraction, while the presence of BO3, BO4, P–O–P, PO4, P–O–B, O–P–O, SO4 and B–O–B units was determined via FTIR study. Glass density and molar volume were found to be between 2.203 to 2.222 g cm−3 and 48.10 to 48.80 m3 mol−1, respectively. The direct and indirect bandgap and Urbach’s energy were found to be within 4.183–4.312 eV, 3.423–3.718 eV and 0.381–0.447 eV energy ranges, respectively. The absorption spectra displayed nine prominent peaks centered at 351, 383, 451, 752, 799, 896, 1090, 1269 and 1670 nm corresponding to 6H15/2 → 6P7/2, 4F7/2, 4I15/2, 6F3/2, 6F5/2, 6F7/2, 6F9/2, 6H11/2 and 6H11/2 transitions. The emission spectrum of calcium sulfoborophosphate glasses doped with Dy3+ shows two prominent bands at 482 nm (4F9/2 → 6H15/2) and 572 nm (4F9/2 → 6H13/2) and two weak bands at 661 nm (4F9/2 → 6H11/2) and 684 nm (4F9/2 → 6H9/2) under 345 nm excitation. The calculated bonding parameters (δ) were found to be ionic in nature. Judd–Ofelt parameters Ωλ (λ = 2, 4 and 6) have been calculated from the absorption spectra. The emission cross sections, as well as the branching ratios for two intense emission transitions 4F9/2 → 6H15/2 and 4F9/2 → 6H13/2, have been calculated. The excellent features demonstrated by the present glasses amplify their suitability for solid-state lasers, nonlinear optical and white LEDs applications.