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Spectroscopic properties of Er 3+ ions in lead-free oxyfluoride germanate glasses were studied. The absorption and luminescence spectra of Er 3+ ions were examined for glass samples with low and high BaF 2 content. From absorption spectra the bonding parameter was calculated and its value is reduced with increasing BaF 2 content. The maximum of absorption peak due to 4 I 15/2 − 2 H 11/2 hypersensitive transition is shifted to shorter wavelengths (blue shift) with increasing BaF 2 content. Luminescence spectra and their decays corresponding to main 4 I 13/2 − 4 I 15/2 laser transition of Er 3+ are also presented and discussed. Quite long-lived near-infrared luminescence of Er 3+ is observed for lead-free glass samples with low BaF 2 concentration. [ABSTRACT FROM AUTHOR]

Series of lead-free borate glasses with different oxide modifiers and lanthanide ions were prepared. The effect of oxide modifiers MO (M = Ca, Sr, Ba) on spectroscopic properties of trivalent Ln 3+ (Ln = Eu, Er, Pr) were systematically investigated. Especially, the luminescence spectra of Ln 3+ -doped lead-free borate glasses are presented and discussed in relation to the impact of selective components (CaO, SrO and BaO). Several spectroscopic parameters, such as the fluorescence intensity ratio R/O (Eu 3+ ) and measured luminescence lifetimes for the 5 D 0 (Eu 3+ ), 4 I 13/2 (Er 3+ ) and 1 D 2 (Pr 3+ ) excited states of lanthanide ions were analyzed in details. The research proved that spectroscopic properties of trivalent Ln 3+ depend significantly on kind of presence oxide modifiers MO (M = Ca, Sr, Ba) in glass host matrices. [ABSTRACT FROM AUTHOR]

In this research, the effects of fluoride ions concentration on luminescence properties of Eu 3+ :PbF 2 nanocrystals in silicate sol–gel materials have been investigated. Optical and structural properties of Eu 3+ :PbF 2 nanocrystals have been examined using X-ray diffraction analysis (XRD) and luminescence spectroscopy. Formation of the cubic β-PbF 2 nanocrystalline phase was confirmed. The crystal size was estimated using Scherrer's equation and Williamson-Hall formula. The optical behavior of Eu 3+ ions in studied materials is strongly dependent on amount of incorporated fluorides in the host lattice and the optimal concentration about 3.0 mass. % give the more intense emission of Eu 3+ . The luminescence spectra showed the characteristic orange-red emission due to the 5 D 0 → 7 F 1 and 5 D 0 → 7 F 2 electron transitions, respectively. The luminescence intensity ratio R (I( 5 D 0 → 7 F 2 )/I( 5 D 0 → 7 F 1 )) and luminescence lifetimes for the 5 D 0 excited state of Eu 3+ ions were determined for each sample before and after heat treatment process. Obtained results indicate the partially incorporation of Eu 3+ ions into β-PbF 2 nanocrystalline phase during ceramization process. [ABSTRACT FROM AUTHOR]