Structural properties and luminescence of rare-earth ions in transition-metal fluoride glasses

Influence of PrCl3/PrF3 on the optical and spectroscopic properties of fluorogallate and fluoro-gallo-indate glasses

“…A similar behavior was observed for the lifetime of the 4 S 3/2 level of Er 3+ comparing PZG glasses doped by ErCl 3 or ErF 3 [13,15]. A possible explanation can be given in terms of a reduction of the phonon energy, which induces a decrease of the multiphonon relaxation rate.…”

“…In Pr 3+ , the small (E gap $ 2500 cm À1 ) 1 G 4 -3 F 4 gap causes rapid relaxation and 1300 nm luminescence is effective only in low-phonon-frequency hosts [15]. Fig.…”

“…This can be done by modifying the local structure in a larger phonon energy host, by incorporating other dopants or phases with lower phonon energies. In particular, increase of the lifetime has been reported with the incorporation of chloride in the glass either as a compound of the glass matrix [12][13][14] or as a precursor of the dopant ion [15] despite the conclusion of Braglia et al [16] in a study of Pr-doped fluorozirconate glasses that the local RE 3+ environment is independent of the doping precursor. In fact, substitution of fluorine by chlorine, through the reduction of the multiphonon relaxation rate, enhances the emission quantum yield of RE 3+ emitting levels.…”