GOLD NANOPARTICLES ENHANCED OPTICAL PROPERTIES OF Sm3+ DOPED SODIUM-LITHIUM-TELLURITE GLASS

Abstract

Enhancing the optical properties of rare earth (RE) doped tellurite glasses by embedding metallic nanoparticles (NPs) with controlled size and optimized concentration is ever-demanding in solid state lasing materials. The influences of gold (Au) NPs concentration on the optical and structural enhancements of sodium-lithium tellurite glass are examined. Glasses with compositions 79TeO₂+10Li₂O+10Na₂O+1Sm₂O₃+yAuCl₃ (where 0.03 ≤ y ≤ 0.15 mol%) are prepared using melt-quenching technique and optical characterizations are made. Subsequent heat treatment (annealing) at 300°C for 3 hours is performed to control the growth of NPs. During melting, first Au+ ions are formed and then reduced to Au0 via redox reaction. Anneling above the glass transition temperature facilitates Au0 to aggregate and form NPs. The annealing assisted NPs growth occurs via coarsening. XRD pattern confirms the amorphous nature of the prepared glasses. The TEM image reveals the growth of Au NPs with mean size ~18 nm. The enhancement in luminescence is attributed to the surface plasmon resonance effect and strong local field of NPs positioned in the proximity of Sm³⁺ ion. The presence of Au NPs alters the glass network structure and significantly modifies the physical, structural, and optical properties. The mechanism of enhancement is understood in terms of various mechanisms and compared. The excellent features of our results may nominate these glasses as a potential candidate for solid state laser, display, and amplifier.