Upconversion emission of Tm3+ doped germinate tellurite glasses with Au-Ag core-shell nanoparticles

Rare-earth (RE) with metal nanoparticle (NPs) doped glasses greatly contribute to enhancement in visible and NIR emission of the RE ions due to local surface plasmon resonance (SPR). The germinates tungsten tellurite glasses composition of TeO2−GeO2−Li2O-WO3−Yb2O3−Tm2O3− xAu(NO3)3−yAgNO3 with (x= 0.03-0.3 and y=0.006 mol%) - nanoparticles embedded glasses using melt quenching technique have been synthesized and reheated 10hrs for the growth of core-shell bimetallic (Au0−Ag0) nanoparticles in glasses. The absorption spectrum of Tm3+ in germinates tellurite glass containing (Au0 −Ag0) nanoparticles shows peaks from ground state (3H6) variation near 400-540nm due to SPR bands. Also,upconversion emission enhancement in 653nm red (1G4→3H6) has been observed at 980nm excitation at room temperature and enhancement is found to be about ∼2 folds due to SPR. The Confocal fluorescence was used to observe the image of fluorescence of Ag-Au NPs core-shell in the glass under 488nm laser excitation. On doping percentage of Au and Ag for the formation of core-shell glass,samples are attributed to maximum enhancement due to the local field on the Tm3+ ions locations and explained by the energy transfer mechanism. Results show that core-shell Au- Ag NPs play a significant role in enhancement red emission of Tm3+ ions and this hybrid-nano composite may be used for laser-based applications.