The influence of Ag content and annealing time on structural and optical properties of SGS antimony-germanate glass doped with Er 3þ ions J. Zmojda a, * , M. Kochanowicz a , P. Miluski a , A. Baranowska b , A. Basa c , R. Jadach d , M. Sitarz d , D. Dorosz d a Faculty of Electrical Engineering, Bialystok University of Technology, Wiejska Street 45D,15-351 Bialystok, Poland b Faculty of Mechanical Engineering, Bialystok University of Technology, Wiejska Street 45B,15-351 Bialystok, Poland c Institute of Chemistry, University of Bialystok, ul. Ciolkowskiego 1K, 15-245 Bialystok, Poland d Faculty of Materials Science and Ceramics, AGH University of Science and Technology, 30 Mickiewicza Av., 30-059 Krakow, Poland article info Article history: Received 29 December 2017 Received in revised form 7 February 2018 Accepted 8 February 2018 Available online 9 February 2018 Keywords: Local field effect Ag nanoparticles Erbium ions Antimony-germanate glass Luminescence properties Raman spectra abstract A series of erbium doped SGS antimony-germanate glass embedding silver (Ag 0 ) nanoparticles have been synthesized by a one-step melt-quench thermochemical reduction technique. The effect of NPs con- centration and annealing time on the structural and photoluminescent (PL) properties were investigated. The Raman spectra as a function of temperature measured in-situ allow to determine the structural changes in vicinity of Ag þ ions and confirmed thermochemical reduction of Ag þ ions by Sb 3þ ions. The surface plasmon resonance absorption band was evidenced near 450 nm. The impact of local field effect generated by Ag 0 nanoparticles (NPs) and energy transfer from surface of silver NPs to trivalent erbium ions on near-infrared and up-conversion luminescence was described in terms of enhancement and quench phenomena. © 2018 Elsevier B.V. All rights reserved. 1. Introduction In the fields of nanotechnology and nanophotonics, the new glasses with noble metal nanoparticles are very attractive material with unique optical properties and huge potential of applications such as solar cells, frequency up-converters, biosensors, optical waveguides and amplifiers [1e8]. The reason is that the collective oscillation of the noble metal free electrons resonantly excited by visible light causes a tremendous enhancement of the electro- magnetic near-field in the vicinity of nanoparticles. If this phe- nomenon, called surface plasmon resonance (SPR), exists in inorganic glasses doped with rare-earth (RE) ions, the lumines- cence signal may be amplified or quenched. In fact there are many important key factors, such as particles size and geometry, refrac- tive index of glass, concentration of metal ions and excitation wavelength, which influence the interaction mechanisms of dopants with light and the energy transfer between RE ions and nanometals [9]. Another important factor is the proper selection of the inorganic host for metal nanoparticles embedding. Up to now, the SPR phenomenon has been investigated in many different hosts such as tellurite [10], phosphate [11], silicate [12, 13] and antimony [14] glasses. Especially, antimony oxide based glasses have attrac- ted a considerable interest for their combination of chemical durability, low phonon energies (~600 cm 1 ) and high trans- parency in a wide range. However, the low field strength (0.73) of Sb 3þ makes it a poor glass former and it is unable to exist, partic- ularly in the bulk monolithic form which is very much essential for practical applications. In our earlier investigations, we proposed the solution of this problem and synthesized a glass with a com- bination of different phonon energy of glass-forming elements [15, 16]. Another important fact is that Sb 2 O 3 is a mild reducing agent of noble metal ions. This mild reduction property enables in- situ reduction of Ag þ (AgNO 3 ) to Ag 0 in a single-step during the melting process, thereby providing a simple, low cost method for the preparation of bulk photonic materials. Among rare-earth ions, the erbium is considered as the most * Corresponding author. E-mail address: j.zmojda@pb.edu.pl (J. Zmojda). Contents lists available at ScienceDirect Journal of Molecular Structure journal homepage: http://www.elsevier.com/locate/molstruc https://doi.org/10.1016/j.molstruc.2018.02.030 0022-2860/© 2018 Elsevier B.V. All rights reserved. Journal of Molecular Structure 1160 (2018) 428e433