Plasmonic AuxAgy bimetallic alloy nanoparticles enhanced photoluminescence upconversion of Er3+ ions in antimony glass hybrid nanocomposites

Er3+ ions and spherical (3-23 nm) AuxAgy bimetallic alloy (where x = 18-96 and y = 4-82, atom %) nanoparticles incorporated novel antimony oxide based reducing dielectric (glass) matrix, K2O-B2O3-Sb2O3 (KBS), has been synthesized by a new single step methodology involving selective thermochemical reduction. Their absorption spectra show a single tunable (536-679 nm) surface plasmon resonance band along with the typical absorption peaks of the Er3+ ion. X-ray and SAED indicate the formation of (111) and (200) planes of AuxAgy alloy. The luminescence intensity of 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 were observed to be strongly dependent on the AuxAgy nanoparticle composition. Both the bands undergo a maximum of 1.5- and 4.5-fold intensity enhancement respectively in the presence of the Ag56Au44 alloy (atom %) due to plasmon induced local field enhancement.