Nanosilver enhanced upconversion fluorescence of erbium ions in Er3+: Ag-antimony glass nanocomposites

Er3+: Ag-antimony glass nanocomposites are synthesized in a new reducing glass (dielectric) matrix K2O-B2O3-Sb2O3 by a single-step melt-quench technique involving selective thermochemical reduction. The UV-vis-near-infrared absorption spectra show typical surface plasmon resonance (SPR) band of Ag-0 nanoparticles (NPs) in addition to the distinctive absorption peaks of Er3+ ion. X-ray diffraction and selected area electron diffraction results indicate formation of Ag-0 NPs along the (200) plane direction. The transmission electron microscopic image reveals the formation of spherical, fractal, and rod-shaped Ag-0 NPs having maximum size similar to 31 nm. The rod-shaped Ag-0 NPs have aspect ratio similar to 2.4. The field emission scanning electron microscopic image shows development of three dimensional cornlike microstructures. Photoluminescent upconversion under excitation at 798 nm exhibit two prominent emission bands of Er3+ ions centered at 536 (green) and 645 (red) nm due to S-4(3/2) -> I-4(15/2) and F-4(9/2) -> I-4(15/2) transitions, respectively. Both the bands undergo a maximum of three-and eightfold intensity enhancement, respectively, at Ag-0 concentration of 0.007 wt % (1.8 X 10(18) atoms/cm(3)). Local field enhancement induced by Ag-0 SPR is found to be responsible for enhancement while energy transfer from Er3+. Ag-0 and optical reabsorption due to Ag-0 SPR for quenching. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3054918]