Funct. Mater. 2014; 21 (4): 498-502.

http://dx.doi.org/10.15407/fm21.04.498

Energy transfer in co-doped NaI:(Tl,Eu) crystals

S.Gridin[1,2], S.Vasyukov[1], N.Shiran[1], A.Gektin[1]

[1] Institute for Scintillation Materials, 60 Lenin Avenue, 61001 Kharkov, Ukraine

[2] Institut Lumiere Matiere, Universite Claude Bernard Lyon 1, 69622 Villeurbanne Cedex, France

Abstract: 

The energy transfer mechanism in Eu doped and Tl, Eu co-doped NaI crystals is discussed. The self-trapped exciton emission band overlaps stronger with Eu2+ excitation bands rather that with Tl+. This suggests that transfer STE -> Activator can be more efficient in Eu2+ co-doped NaI:Tl crystals. Theoretical estimation of energy transfer efficiency was done based  on the Forster model. It is shown that Europium concentration of 1 mass% or above is required for efficient dipole-dipole energy transfer. However, this concentration is not reachable in NaI:(Tl,Eu) due to the solubility limit of Eu2+ in NaI crystal.

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