Tailored optical properties of Dy3+ doped magnesium zinc sulfophosphate glass: Function of silver nanoparticles embedment

Glasses with composition (59.5-x)P2O5-20.0MgO-20.0ZnSO4-0.5Dy2O3-xAgCl (0.0≤x≤ 0.5 mol%) were prepared by melt-quenching method and characterized thoroughly. The role of silver nanoparticles (Ag NPs) inclusion on the spectroscopic and the physical properties of the synthesized glasses were determined. Judd-Ofelt (J-O) theory was used to complement the experimental optical data. TEM images confirmed the existence of Ag NPs of average size ≈4.5 nm. The absorption spectra showed eleven bands aroused from the ground state (6I15/2) to various excited states transitions of dysprosium (Dy3+) ion. The surface plasmon resonance (SPR) peak of Ag NPs was probed around 446 nm. The calculated J-O parameter (Ω2) for the glass without Ag NPs incorporation was the highest, indicating the strong metal-ligand covalence bond. Irrespective of Ag NPs contents, the emission spectra of the studied glasses revealed two intense photoluminescence bands centered at 480 nm (blue: 4F9/2→6H15/2) and 574 nm (yellow: 4F9/2→6H13/2) accompanied by two very weak red bands positioned at 662 and 752 nm. The luminescence intensity of both blue and yellow band was enhanced by a factor of 2 and it was 1.5 fold for the red bands. This enrichment in the luminescence intensity was attributed to the Ag NPs mediated SPR effect and subsequent energy transfer from the Ag NPs to the nearsighted Dy3+ ions.