Energy transfer based photoluminescence spectra of co-doped (Dy3+ + Sm3+): Li2O-LiF-B2O3-ZnO glasses for orange emission

The present paper brings out the results concerning the preparation and optical properties of Sm³⁺ and Dy³⁺ each ion separately in different concentrations (0.3, 0.5, 1.0 and 1.5 mol.%) and also together doped (x mol.% Dy³⁺ + 1.5 mol.% Sm³⁺): Li₂O-LiF-B₂O₃-ZnO (where x = 0.5, 1.0 and 1.5 mol.%) glasses by a melt quenching method. Structural and thermal properties have been extensively studied for those glasses by XRD and TG/DTA. The compositional analysis has been carried out from FTIR spectral profile. Optical absorption spectral studies were also carried out. Sm³⁺: LBZ glasses have displayed an intense orange emission at 603 nm (⁴G_5/2 → ⁶H_7/2) with an excitation wavelength at 403 nm and Dy³⁺: LBZ glasses have shown two emissions located at 485 nm (⁴F_9/2 → ⁶H_15/2; blue) and 574 nm (⁴F_9/2 → ⁶H_13/2; yellow) with an excitation wavelength at 385 nm. Remarkably, it has been identified that the significant increase in the reddish orange emission of Sm³⁺ ions and diminished yellow emission pertaining to Dy³⁺ ions in the co-doped LBZ glass system under the excitation of 385 nm which relates to Dy³⁺ ions. This could be due energy transfer from Dy³⁺ to Sm³⁺. The non-radiative energy transfer from Dy³⁺ to Sm³⁺ is explained in terms of their emission spectra, donor lifetime, energy level diagram and energy transfer characteristic factors. These significantly enhanced orange emission exhibited glasses could be suggested as potential optical glasses for orange luminescence photonic devices.