Temperature dependence of the photostimulated luminescence of X-irradiate BaFBr:Eu²⁺

Abstract

The temperature dependence of the luminescence from activators in BaFBr : EuZt photostimulated between 10 and 300 Kin the optical absorptions of F centres produced by room temperature x-irradiation, revealed two thermally-activated processes. The photostimulated luminescence (PSL) increases sharply inintensity when excited between 60 and 100 K. After the low-temperature PSL is exhausted by continuous F centre excitation, it can be almost entirely regained by warming the crystal to 300 K. This thermal cycle can be repeated several times. It is shown by EPR that no Eu3+ is formed upon x-irradiation at 300 K. These results are explained with a model for the PSL mechanism which involves a loose aggregate of E d t , F, and hole centres.

Light-induced valence-state switching in BaFCl:La and SrFCl:La

“…Generally speaking, the basic oxygen centers O Ϫ (F Ϫ ), O Ϫ (Cl Ϫ ), and O 2 Ϫ (Cl Ϫ ) in BaFCl are well understood. 7,10 Our results agree with the published ones as regards these systems. The situation is different for SrFCl where very few published results exist ͑see, however, Ref.…”

Photostimulable x-ray storage phosphors: a review of present understanding

“…4. By investigations of Hangleiter et al 32 and Koshnick et al 33 the Eu 2+ ion captures the hole without the formation of Eu 3+ as was believed initially 31 . This result is in agreement with other groups 34 .…”

Room-temperature emission-color switching of Ba 3 MgSi 2 O 8 : Eu 2+ and the photochemical reaction mechanism

“…When the Ba 3 MgSi 2 O 8 : Eu 2+ is exposed to photostimulation, the electrons trapped in V O are once excited into conduction band, and then, decay near Eu 2+ [18][19][20][21]. Since the Eu 2+ -associated electron feels additional electrostatic potential from the neighboring Eu 2+ , it has bound levels different from those of F centers.…”