Silver nanoparticle enhanced the optical properties of the rare earth doped magnesium-zinc-sulfophosphate glass

Abstract

Magnesium-zinc-sulfophosphate (P2O5-MgO-ZnSO4) glasses being a prospective host for lasing active media require precise composition optimization and systematic characterization. A series of glass samples in the composition of (60.0- x)P2O5-20.0MgO-20.0ZnSO4-xRE2O3 (0.0 ≤ x≤ 2.0 mol% and rare earth (RE) = Sm, Dy, and Er), (59.5-y)P2O5-20.0MgO-20.0ZnSO4-0.5RE2O3-yAgCl (0.0 ≤ y ≤ 0.5 mol% and RE = Sm and Dy) and (59.5-z)P2O5-20.0MgO-20.0ZnSO4-0.5Er2O3-zAgCl (0.0 ≤ z≤ 1.5 mol%) were synthesized using melt-quenching technique. The samples were thoroughly characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FTIR), ultraviolet-visible (UV-Vis) absorption, photoluminescence (PL) and Raman spectroscopy. XRD verified the samples amorphous nature and TEM images manifested the nucleation of homogeneously distributed spherical silver (Ag) nanoparticles in the glass matrix. FTIR spectra revealed the bonding vibrations for P-O bonds, P-O-P linkages, and PO2 units. There is no evidence in Raman spectra of RE (RE= Sm, Dy and Er) doped P2O5- MgO-ZnSO4 glasses to confirm the incorporation of the sulfate ions to the network formation. The absorption spectrum of RE (RE = Sm, Dy and Er) doped P2O5-MgOZnSO4 glasses with and without incorporation of Ag nanoparticles is originated from electronic transitions from the ground level to various excited levels belonging to the 4f9 electronic configuration of the RE ions. Absorption and emission spectra are used to evaluate the Judd-Ofelt (JO) intensity parameters and radiative transition probabilities, branching ratios and stimulated emission cross-sections of the three RE ion (RE = Sm, Dy, and Er) doped glass systems. The room temperature PL spectra of samarium-doped glass revealed four emission peaks centered at around 562, 599, 644, and 702 nm, which are assigned to the transitions from 4G5/2 to 6H5/2, 6H7/2, 6H9/2 and 6H11/2, respectively. The PL spectra of dysprosium-doped glass displayed two prominent peaks at around 480 nm and 574 nm corresponding to the 4F9/2→6H15/2 and 4F9/2→6H13/2 transitions, respectively and two weak peaks. Conversely, erbium-doped glass system exhibited two strong emission peaks centered at around 541 nm and 654 nm attributed to the 4S3/2→4I15/2 and 4F9/2→4I15/2 transitions, respectively. All glass series containing Ag nanoparticles showed considerable emission intensity enhancement, which is attributed to the nanoparticle surface plasmon resonance mediated intensified local field effect in the proximity of RE ions. Overall properties of each glass series are demonstrated to be modified due to the embedment of Ag nanoparticles. Among all the glass series produced, the stimulated emission crosssection for 4S3/2→4I15/2 transition in erbium-doped glass system is discerned to be the highest.