Enhancement of Er3+ upconverted luminescence in Er3+: Au-antimony glass dichroic nanocomposites containing hexagonal Au nanoparticles

Dichroic Er3+:Au-antimony glass nanocomposites are synthesized in a new reducing glass (dielectric) matrix (mol%) K2O-B2O3-Sb2O3 (KBS) by a single-step melt-quench technique involving selective thermochemical reduction principle. Transmission electron microscopic images reveal hexagonal Au-0 nanoparticles having major axes about 9 23 nm. Dichroic behavior arises due to hexagonal Au-0 nanoparticles of aspect ratio 1.2-1.3. Auo nanoparticles of concentration of 0.03 wt% (4.1 x 10(18) atoms/cm(3)) drastically enhances the intensity (2-5 folds) of both 536 (S-4(3/2) -> I-4(15/2), green) and 645 (F-4(9/2) -> I-4(15/2), red) nm emission bands of Er3+. Local field enhancement induced by Au-0 surface plasmon resonance (SPR) and energy transfer from fluorescent Au-0. Er3+ ions are found to be responsible for enhancement while, at very high Au concentration, energy transfer from Er3+ -> Au-0 and optical reabsorption due to Au-0 SPR result in quenching. (C) 2009 Optical Society of America