EPR results and Raman spectroscopy as a complementary characterization of isolated Yb ions and Yb pairs in CaF2:Yb single crystals

Evolution of Yb3+ environment and luminescence properties under ionizing irradiation in aluminoborosilicate glasses

“…This hypothesis seems to be more relevant because of the cooperative luminescence behavior; the important decrease at low irradiation dose indicates an efficient reduction process into the clustered sites. This interpretation is supported by Kaczmarek et al [34] who evidenced the formation of Yb 3+ -Yb 2+ pairs in CaF 2 single crystals under gamma irradiation.…”

Understanding Enhanced Upconversion Luminescence in Oxyfluoride Glass-Ceramics Based on Local Structure Characterizations and Molecular Dynamics Simulations

“…Figure a demonstrates the Raman spectra of G­(Er:Yb) and GC­(Er:Yb) at an excitation wavelength 514.5 nm. The glass sample G­(Er:Yb) reveals a rather broadened and smoothed spectrum, typical for an amorphous material, while the characteristic vibration bands of SiO 4 , AlO 4 , and F–Ca can be still clearly observed. ,, The appearance of the T 2g vibration mode for F–Ca bonds centered around 311 cm –1 may imply that phase separation into a fluoride-rich and fluoride-deficient region happens in the as-melt glass, which acts as a nucleation agent of the CaF 2 nanocrystals in the GCs. In the spectrum of GC­(Er:Yb), the small but sharp peak at 140 cm –1 can be ascribed to the crystalline CaF 2 phase, while the broad hump at 311 cm –1 that can be ascribed to the F–Ca vibration mode remains unchanged.…”

“…The glass sample G(Er:Yb) reveals a rather broadened and smoothed spectrum, typical for an amorphous material, while the characteristic vibration bands of SiO 4 , AlO 4 , and F−Ca can be still clearly observed. 21,22,33 The appearance of the T 2g vibration mode for F−Ca bonds centered around 311 cm −1 may imply that phase separation into a fluoride-rich and fluoride-deficient region happens in the as-melt glass, which acts as a nucleation agent of the CaF 2 nanocrystals in the GCs.…”