Influence of Tl+ activator ions on the luminescence characteristics of KCl0.5Br0.5:Eu2+ powder phosphors

Photoluminescence (PL) of thallium co‐doped with KCl_0.5Br_0.5:Eu²⁺ powder phosphors display emission bands at 320 and 370 nm attributable to centres involving Tl⁺ ions in addition to characteristic Eu²⁺ emission around 420 nm. Additional PL excitation and emission bandS observed around 260 and 380 nm, respectively, were observed in the double‐doped KCl_0.5Br_0.5:Eu²⁺, Tl⁺ powder phosphors and are attributed to complex centres involving Tl⁺ and Eu²⁺ ions. The enhancement observed in the intensity of Eu²⁺ emission around 420 nm with the addition of TlBr in KCl_0.5Br_0.5:Eu²⁺ powder phosphors is attributed to the energy transfer from Tl⁺ → Eu²⁺ ions. Photostimulated luminescence (PSL) studies of γ‐irradiated KCl_0.5Br_0.5:Eu²⁺, Tl⁺ mixed phosphors are reported and a tentative PSL mechanism in the phosphors has been suggested. Copyright © 2009 John Wiley & Sons, Ltd.