Optical, luminescence, and energy transfer studies of Gd³⁺/Dy³⁺ doped potassium gadolinium borophosphate glasses

Abstract

The K2O–Gd2O3–B2O3–P2O5 glass doped with Dy2O3 (Dy:KGPB) were synthesized by the melt-quenching technique. These glasses were subjected to characterize the physical, structure, optical and luminescence properties. It was observed that the density, molar volume and refractive index of glass increased with increasing Dy2O3 concentration. The FTIR result confirmed the main glass network of B[dbnd]O[dbnd]B and P[dbnd]O[dbnd]P linkages those were degraded by adding Dy2O3 modifier. Glasses absorbed photons in ultraviolet, visible light and near-infrared region. The photoluminescence under direct Dy3+ excitation performed the strong emissions at 574 and 482 nm corresponding to 4F9/2 → 6H13/2 and 4F9/2 → 6H15/2 transition, respectively. The Gd3+ excitation also caused strong emission of Dy3+ by the Gd3+-Dy3+energy transfer. Glass doped with 1.00 mol% of Dy2O3 owned the highest emission intensity due to the concentration quenching. The lifetime of 4F9/2 level was found to decrease with addition of Dy2O3 content via dipole-diploe interaction between Dy3+ ion. Judd-Ofelt (J-O) intensity parameters were initially calculated and applied to evaluate the radiative parameters such as branching ratios, radiative transition probabilities, and stimulated emission cross-sections. The radioluminescence of glass was also investigated and found the scintillation efficiency around 15.6%, compared to BGO scintillator. The Dy:KGPB glass has an interesting potential for solid-state laser, LED and X-ray detection applications.