Core-shell Au-Ag nanoparticles in dielectric nanocomposites with plasmon-enhanced fluorescence: A new paradigm in antimony glasses

The nano era demands the synthesis of new nanostructured materials, if possible by simplified techniques, with remarkable properties and versatile applications. Here, we demonstrate a new single-step reproducible melt-quench methodology to fabricate core-shell bimetallic (Au 0 -Ag 0 ) nanoparticles (28–89 nm) embedded glasses (dielectrics) by the use of a new reducing glass matrix, K 2 O-B 2 O 3 -Sb 2 O 3 (KBS) without applying any external reducing agent or multiple processing steps. The surface plasmon resonance (SPR) band of these nanocomposites embedded in KBS glass is tunable in the range 554–681 nm. More remarkably, taking advantage of the selective reduction capability of Sb 2 O 3 , this single-step methodology is used to fabricate inter-metallic: rare-earth ions co-embedded (Au-Ag:Sm 3+ ) dielectric (glass)-based-dnanocomposites and study the effect of enhanced local field on the red upconversion fluorescence of Sm 3+ ions at 636 nm. The enhancement is found to be about 2 folds. This single-step in-situ selective reduction approach can be used to fabricate a variety of hybrid-nanocomposite devices for laser based applications (see supplementary information).