Role of the charge-transfer states in feeding and thermally emptying the 5D states of Eu+3 in yttrium and lanthanum oxysulfides

Interpretation of europium(III) spectra

“…They are in general broad without fine structure. [527]. The absence of the Eu 3+ -O 2-CT band in europium(III)-doped fluoride compounds can be used as an indication that no oxygen is built in the fluoride matrix and thus as a method for determination of the purity of fluoride compounds [251].…”

Low‐energy charge‐transfer state and optical properties of Eu 3+ ‐doped GaN

“…3, one may expect that some broad luminescence bands due to the transitions from the charge-transfer state to the 7 F J states are observed in the visible and infrared regions. These transitions would have large rate of the order of 10 7 s -1 because of their parity-allowed electricdipole characters [10]. Contrary to the above expectation, even the time-resolved PL spectrum at delay time of 60 ns after the pulsed excitation (see Fig.…”

“…3 [10]. In this figure, the Franck-Condon shifts between the 4f 6 states are negligibly small, because the 4f electron-phonon interaction is very weak on account of the shielding of the 4f electrons from the surroundings by outer 5s 2 and 5p 6 electrons.…”

“…This is because the 4f shell of Eu 3+ (4f 6 configuration) readily receives an electron from the host crystal (or ligand) for the stability of the half-filled electron shell of the 4f 7 configuration. The charge-transfer state of Eu 3+ is known to affect much the luminescence properties of the ion, such as the strengths and the luminescence thermal quenching behaviors of the f-f transitions [9][10][11][12][13][14][15][16].…”

A study of the Eu3+ charge-transfer state in lanthanide-borate glasses

“…It has been shown before that in the case of crystalline solids the position of the CTS has a large influence on the luminescent efficiency [6][7][8].…”