Spectroscopic attributes of Er3+ ions in antimony phosphate glass incorporated with Ag nanoparticles: Judd-Ofelt analysis

Abstract

This paper reports the detailed Judd-Ofelt (J-O) analysis of Er3+-doped antimony phosphate glass system incorporated with silver nanoparticles (Ag NPs). Such glass system of composition (59.5-x)Sb2O3–35P2O5–5MgO–0.5Er2O3–xAgCl (0 < x < 0.9 mol.%) are synthesized via melt-quenching method. Samples are characterized to determine the influence of Ag NPs concentration dependent modifications in the spectroscopic properties. TEM image manifested the nucleation of Ag NPs of average diameter 4.6 nm and their homogeneous dispersion in the glass matrix. Three surface plasmon resonance (SPR) absorption bands of Ag NPs are probed at 544, 570 and 628 nm. UV–Vis–NIR spectra of glass samples exhibited ten significant absorption peaks of Er3+ ion. Bonding of Er3+ ions with ligands is changed from ionic to covalent character. J-O analysis demonstrated significant increase of Ω2 with increasing the concentration of Ag NPs which indicated an improvement in the covalency and asymmetry of Er3+ ions environment. Down-conversion photoluminescent (PL) spectra displayed eleven emission bands of Er3+ ions in which the intensities are enhanced significantly (as much as 17.33-fold for sample containing 0.5 mol% of Ag NPs) due to the incorporation of Ag NPs. This intensity enlargement is mainly attributed to the SPR mediated local field effect induced by Ag NPs. The achievement of high stimulated cross-section of this glass system makes them prospective for solid state lasers.