Nanosilver enhanced upconversion fluorescence of erbium ions in Er 3+: Ag-antimony glass nanocomposites

Abstract

Er3+:Ag-antimony glass nanocomposites are synthesized in a new reducing glass (dielectric) matrix K2 O- B2 O3 - Sb2 O3 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 Ag0 nanoparticles (NPs) in addition to the distinctive absorption peaks of Er 3+ ion. X-ray diffraction and selected area electron diffraction results indicate formation of Ag0 NPs along the (200) plane direction. The transmission electron microscopic image reveals the formation of spherical, fractal, and rod-shaped Ag0 NPs having maximum size ∼31 nm. The rod-shaped Ag0 NPs have aspect ratio ∼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 S43/2 → I415/2 and F49/2 → I415/2 transitions, respectively. Both the bands undergo a maximum of three- and eightfold intensity enhancement, respectively, at Ag0 concentration of 0.007 wt % (1.8× 1018 atoms/ cm3). Local field enhancement induced by Ag0 SPR is found to be responsible for enhancement while energy transfer from Er3+ → Ag0 and optical reabsorption due to Ag0 SPR for quenching. © 2009 American Institute of Physics.