White and red emitting LaF 3 nanocrystals doped with Eu 2+ and Eu 3+ ions: Spectroscopic and magnetic studies

Structural and luminescence properties of silica powders and transparent glass‐ceramics containing LaF3:Eu3+ nanocrystals

“…Hence, both the 5 D 0 → 7 F 1 (MD) and the 5 D 0 → 7 F 2 (ED) transitions of Eu 3+ are well‐observable in registered PL spectra . On the other hand, the relatively high intensity of the 5 D 0 → 7 F 2 ED band could suggests that part of Eu 3+ ions are located on the surface of nanoparticles at the sites of higher asymmetry . The similar PL profiles were obtained for another LaF 3 :Eu 3+ systems described by Grzyb et al, Lunstroot et al and Tian et al .…”

“…On the other hand, the relatively high intensity of the 5 D 0 → 7 F 2 ED band could suggests that part of Eu 3+ ions are located on the surface of nanoparticles at the sites of higher asymmetry . The similar PL profiles were obtained for another LaF 3 :Eu 3+ systems described by Grzyb et al, Lunstroot et al and Tian et al . Otherwise, as was demonstrated in Figures and , the partial incorporation of Eu 3+ optically active ions into low‐phonon LaF 3 crystal phase during controlled ceramization process significantly enhanced the characteristic PL bands, and their intensities have increased compared to sol‐gel amorphous systems.…”

“…Based on obtained results we can conclude that chemical surrounding around Eu 3+ active dopant ions strongly influences their photoluminescence behavior. The luminescence lifetime values of the 5 D 0 excited level of Eu 3+ ions for another LaF 3 :Eu 3+ ‐based systems were presented in Table . As was demonstrated, similar long‐lived photoluminescence have been reported only by Grzyb et al …”

“…The Scherrer equation was used to calculations the average nanocrystals diameters and the mean values were equaled to 40.0 and 8.1 nm for SG1 HT and SG2 HT sol‐gel samples, respectively. For comparison, the crystallite sizes of another LaF 3 :Eu 3+ systems reported in available literature were depicted in Table …”

Controllable synthesis of glass ceramics containing YF3:Eu3+ nanocrystals: Well‐preserved Eu and prolonged lifetime

“…The similar phenomenon has also been published in the (LaF 3 , YF 3 ): Eu 3+ GC system . As is well known, the 5 D 0 → 7 F 1 transition assigned to the magnetic transition is independent of the coordination surroundings around the crystallographic site, while the 5 D 0 → 7 F 2 transition as electric diploe transition is severely influenced by the surrounding environment . That is to say, when Eu 3+ ions locate in a site with inversion symmetry, the 5 D 0 → 7 F 1 transition is dominating, while in a site without inversion symmetry the 5 D 0 → 7 F 2 transition is stronger.…”