Luminescence of Nd3+-doped LaF3 glass-ceramics enhanced with Ag nanoparticles

Nd3+-doped, LaF3-based, transparent oxyfluoride glass-ceramics (GCs) containing Ag nanoparticles (NPs) have been prepared by a melt-quenching method. Different Ag-containing precursors were employed being AgNO3 the most suitable for obtaining Ag NPs segregated in the glassy matrix. Transmission electron microscopy and X-ray absorption spectroscopy determined the presence of Ag0 NPs, with higher concentrations in glass-ceramics produced in an inert atmosphere (N2). The spectral features of emission and excitation spectra, in addition to the different lifetimes of the 4F3/2 state in the co-doped samples with Ag NPs, demonstrate the incorporation of Nd3+ ions into the LaF3 nanocrystals. The relative contribution to the emission from Nd3+ in the nanocrystals depends on the Ag concentration and atmosphere. The glass-ceramic co-doped with 0.2 wt% Ag, thermally treated in N2, exhibits the highest contribution of emissions attributable to Nd3+ ions in the crystalline phase. The crystalline fraction is similar to that of a Ag-free sample synthesized under analogous conditions. This increase of the luminescence is, therefore, attributable to the enhancement of the local electric field of the LaF3 nanocrystals due to the presence of Ag0 NPs.