Plasmon enhanced luminescence of Tb 3+ doped Li 2 O-LaF 3 -Al 2 O 3 -SiO 2 glass containing Ag nanoparticles P. Piasecki, A. Piasecki, Z. Pan*, A. Ueda, R. Aga Jr, R. Mu, and S. H. Morgan Department of Physics, Fisk University, Nashville, TN, USA 37208 ABSTRACT Tb 3+ and Ag co-doped glass nano-composites are synthesized in a glass matrix Li 2 O-LaF 3 -Al 2 O 3 -SiO 2 (LLAS) by a melt- quench technique. The nucleation and growth of Ag nanoparticles (NPs) were controlled by a thermal annealing process. A broad absorption band peaking at about 420 nm was observed due to surface plasmon resonance (SPR) of Ag NPs. Annealing of glass samples results in the growth of Ag NPs. Photoluminescence (PL) emission and excitation spectra were measured from glass samples with different Ag concentrations and different annealing times. Plasmon enhanced Tb 3+ luminescence was observed at certain excitation wavelength regions. Luminescence quenching was observed for samples with high Ag concentration and longer annealing time. Our luminescence results suggest that there are two competitive effects, enhancement and quenching, acting on Tb 3+ luminescence in the presence of Ag NPs. The enhancement of Tb 3+ luminescence is mainly attributed to local field effects: the SPR of Ag NPs causes an intensified electromagnetic field around the NPs, resulting in enhanced optical transitions of Tb 3+ ions in the vicinity. The quenching effect in the presence of Ag NPs suggests an energy transfer from Tb 3+ ions to Ag NPs. The competition between the plasmonic enhancement and the quenching effect is discussed for samples with different Ag concentrations and annealing times. Keywords: Ag, nanoparticle, SPR, Tb 3+ , luminescence 1. INTRODUCTION Rare-earth doped glasses are important for applications in optical devices such as scintillators, optical fiber amplifiers, lasers, optical converters of infrared radiation to visible regions, etc 1- 4 . In addition to the common advantages of low- cost, large-volume production possibility and easy shaping of elements of glasses, oxide glasses generally possess good mechanical strength, chemical durability, and thermal stability. Tb-doped Li 2 O-LaF 3 -Al 2 O 3 -SiO 2 (LLAS) glass was previously reported to have good photoluminescence (PL) and β-induced luminescence light-yield for scintillator application 1 . The incorporation of metallic nanoparticles (NPs) in rare-earth doped glasses may enhance or quench the luminescence of rare-earth ions 5-8 . The enhancement has been attributed to local field enhancement effects on excitation and emission of rare-earth ions and energy transfer from metallic NPs to rare earth ions due to the excitation of SPR of metallic NPs 9 . The quenching effect is due to energy transfer from ions to the metallic NPs 5, 6 . Rare-earth doped glasses containing metallic NPs have recently attracted great interest 7 - 11 . However, in spite of the large amount of work published on this topic, the mechanism of energy transfer from metallic NPs to rare earth ions has not been clarified 5, 6 . In order to further understand the interaction between metallic NPs and rare earth ions in glass, we have studied Tb- doped LLAS glass containing Ag NPs. In present work, we report optical absorption, photoluminescence emission and excitation of Ag co-doped LLAS:Tb glass with different Ag concentrations and annealing times, and discuss the possible mechanisms for plasmonic enhancement and quenching effects on Tb 3+ luminescence. 2. EXPERIMENT Reagent grade anhydrous oxide powders of Li 2 CO 3 , LaF 3 , Al 2 O 3 , SiO 2 , TbF 3 , and AgNO 3 were used to prepare glasses. The compositions of lithium-lanthanum-aluminosilicate glass were 28Li 2 O-11LaF 2 -6Al 2 O 3 -55SiO 2 (LLAS). Four * zpan@fisk.edu Plasmonics: Metallic Nanostructures and Their Optical Properties VIII, edited by Mark I. Stockman, Proc. of SPIE Vol. 7757, 77572M · © 2010 SPIE · CCC code: 0277-786X/10/$18 · doi: 10.1117/12.863061 Proc. of SPIE Vol. 7757 77572M-1