Formation and UV absorption of cerium, europium and terbium ions in different valencies in glasses

Sol–Gel Synthesis of Tunable Cerium Titanate Materials

“…In the case of cerium, 4f-5d bands of Ce 3+ ions and the CT bands of Ce 4+ ions appear in the same wavelength range, what cause them to overlap each other. [39] In our samples, the spectra of those fired at low temperatures (700 and 800ºC) show that the band shifts to higher wavenumber values. This difference clearly indicates a modification in the symmetry and chemical environment of the active cerium ions.…”

White light emission from γ-irradiated Ag/Eu co-doped phosphate glass under NUV light excitation

“…For Eu doped glasses, the charge-transfer absorption bands peaked at about 250 nm and sharp absorption peaks at 393 and 464 nm are assigned to Eu 3+ [30]. The weak peak centered at about 320 nm is due to the 4f-5d transition of Eu 2+ [31], which indicates that a few part of Eu 3+ ions were reduced to Eu 2+ during melting. For acidic glasses, redox equilibria exists for ion couples Eu 3+ /Eu 2+ during glass melting [32][33][34].…”

Terbium-activated heavy scintillating glasses

“…Tb 3+ ion emits fluorescence, but Tb 4+ does not. The Tb 3+ gives several sharp absorption peaks due to f-f transition in the visible region while Tb 4+ has a broad absorption from ultraviolet to visible region peaking at 320-370nm due to the charge transfer transition [7]. It is therefore reasonable to assign the observed broad absorption in the present Tb-doped glasses (Fig.…”