Europium (II)-Doped CaF<sub>2</sub> Nanocrystals in Sol-Gel Derived Glass-Ceramic: Luminescence and EPR Spectroscopy Investigations
The remarkable properties of Eu<sup>2+</sup>-activated phosphors, related to the broad and intense luminescence of Eu<sup>2+</sup> ions, showed a high potential for a wide range of optical-related applications. Oxy-fluoride glass-ceramic containing Europium (II)-doped CaF<...
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MDPI AG
2022-08-01
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| author | Corina Secu Arpad-Mihai Rostas Mihail Secu |
| author_facet | Corina Secu Arpad-Mihai Rostas Mihail Secu |
| author_sort | Corina Secu |
| collection | DOAJ |
| description | The remarkable properties of Eu<sup>2+</sup>-activated phosphors, related to the broad and intense luminescence of Eu<sup>2+</sup> ions, showed a high potential for a wide range of optical-related applications. Oxy-fluoride glass-ceramic containing Europium (II)-doped CaF<sub>2</sub> nanocrystals embedded in silica matrix were produced in two steps: glass-ceramization in air at 800° with Eu<sup>3+</sup>-doped CaF<sub>2</sub> nanocrystals embedded followed by Eu<sup>3+</sup> to Eu<sup>2+</sup> reduction during annealing in reducing atmosphere. The broad, blue luminescence band at 425 nm and with the long, weak tail in the visible range is assigned to the d → f type transition of the Eu<sup>2+</sup> located inside the CaF<sub>2</sub> nanocrystals in substitutional and perturbed sites, respectively; the photoluminescence quantum yield was about 0.76. The X-ray photoelectron spectroscopy and Electron paramagnetic spectroscopy confirmed the presence of Eu<sup>2+</sup> inside the CaF<sub>2</sub> nanocrystals. Thermoluminescence curves recorded after X-ray irradiation of un-doped and Eu<sup>2+</sup>-doped glass-ceramics showed a single dominant glow peak at 85 °C related to the recombination between F centers and Eu<sup>2+</sup> related hole within the CaF<sub>2</sub> nanocrystals. The applicability of the procedure can be tested to obtain an oxy-fluoride glass-ceramic doped with other divalent ions such as Sm<sup>2+</sup>, Yb<sup>2+</sup>, as nanophosphors for radiation detector or photonics-related applications. |
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| spelling | doaj.art-58530c9cfa194bbda72baa3203631c072023-11-23T13:49:26ZengMDPI AGNanomaterials2079-49912022-08-011217301610.3390/nano12173016Europium (II)-Doped CaF<sub>2</sub> Nanocrystals in Sol-Gel Derived Glass-Ceramic: Luminescence and EPR Spectroscopy InvestigationsCorina Secu0Arpad-Mihai Rostas1Mihail Secu2National Institute of Materials Physics, Atomistilor 405A, 077125 Magurele, RomaniaNational Institute of Materials Physics, Atomistilor 405A, 077125 Magurele, RomaniaNational Institute of Materials Physics, Atomistilor 405A, 077125 Magurele, RomaniaThe remarkable properties of Eu<sup>2+</sup>-activated phosphors, related to the broad and intense luminescence of Eu<sup>2+</sup> ions, showed a high potential for a wide range of optical-related applications. Oxy-fluoride glass-ceramic containing Europium (II)-doped CaF<sub>2</sub> nanocrystals embedded in silica matrix were produced in two steps: glass-ceramization in air at 800° with Eu<sup>3+</sup>-doped CaF<sub>2</sub> nanocrystals embedded followed by Eu<sup>3+</sup> to Eu<sup>2+</sup> reduction during annealing in reducing atmosphere. The broad, blue luminescence band at 425 nm and with the long, weak tail in the visible range is assigned to the d → f type transition of the Eu<sup>2+</sup> located inside the CaF<sub>2</sub> nanocrystals in substitutional and perturbed sites, respectively; the photoluminescence quantum yield was about 0.76. The X-ray photoelectron spectroscopy and Electron paramagnetic spectroscopy confirmed the presence of Eu<sup>2+</sup> inside the CaF<sub>2</sub> nanocrystals. Thermoluminescence curves recorded after X-ray irradiation of un-doped and Eu<sup>2+</sup>-doped glass-ceramics showed a single dominant glow peak at 85 °C related to the recombination between F centers and Eu<sup>2+</sup> related hole within the CaF<sub>2</sub> nanocrystals. The applicability of the procedure can be tested to obtain an oxy-fluoride glass-ceramic doped with other divalent ions such as Sm<sup>2+</sup>, Yb<sup>2+</sup>, as nanophosphors for radiation detector or photonics-related applications.https://www.mdpi.com/2079-4991/12/17/3016nanocrystalsglass ceramicCaF<sub>2</sub>europiumluminescence |
| spellingShingle | Corina Secu Arpad-Mihai Rostas Mihail Secu Europium (II)-Doped CaF<sub>2</sub> Nanocrystals in Sol-Gel Derived Glass-Ceramic: Luminescence and EPR Spectroscopy Investigations Nanomaterials nanocrystals glass ceramic CaF<sub>2</sub> europium luminescence |
| title | Europium (II)-Doped CaF<sub>2</sub> Nanocrystals in Sol-Gel Derived Glass-Ceramic: Luminescence and EPR Spectroscopy Investigations |
| title_full | Europium (II)-Doped CaF<sub>2</sub> Nanocrystals in Sol-Gel Derived Glass-Ceramic: Luminescence and EPR Spectroscopy Investigations |
| title_fullStr | Europium (II)-Doped CaF<sub>2</sub> Nanocrystals in Sol-Gel Derived Glass-Ceramic: Luminescence and EPR Spectroscopy Investigations |
| title_full_unstemmed | Europium (II)-Doped CaF<sub>2</sub> Nanocrystals in Sol-Gel Derived Glass-Ceramic: Luminescence and EPR Spectroscopy Investigations |
| title_short | Europium (II)-Doped CaF<sub>2</sub> Nanocrystals in Sol-Gel Derived Glass-Ceramic: Luminescence and EPR Spectroscopy Investigations |
| title_sort | europium ii doped caf sub 2 sub nanocrystals in sol gel derived glass ceramic luminescence and epr spectroscopy investigations |
| topic | nanocrystals glass ceramic CaF<sub>2</sub> europium luminescence |
| url | https://www.mdpi.com/2079-4991/12/17/3016 |
| work_keys_str_mv | AT corinasecu europiumiidopedcafsub2subnanocrystalsinsolgelderivedglassceramicluminescenceandeprspectroscopyinvestigations AT arpadmihairostas europiumiidopedcafsub2subnanocrystalsinsolgelderivedglassceramicluminescenceandeprspectroscopyinvestigations AT mihailsecu europiumiidopedcafsub2subnanocrystalsinsolgelderivedglassceramicluminescenceandeprspectroscopyinvestigations |