LAUSR

Abstract A new Eu2+, Dy3+: Sr2B5O9Cl phosphor with long persistence was synthesized in a reducing atmosphere by a solid-state reaction process. The pure-phase phosphor was obtained by calcination at 900 °C. The introduction of Eu2+ into the lattice of the matrix resulted in a broad blue emission centered at 423 nm, which was due to the characteristic 4f65d1 to 4f7 energy transfer of Eu2+ ions. Both Eu-doped and Dy/Eu-codoped phosphors displayed afterglow behaviors due to the electron traps generated by the incorporation of tri-valanced rare earth cations into the original Sr lattice sites. The afterglow of Eu2+: Sr2B5O9Cl and Eu2+, Dy3+: Sr2B5O9Cl phosphors showed standard double exponential decay behaviors, and the Eu2+/Dy3+ co-doped sample demonstrated better afterglow properties than Eu2+-doped one. A longer lifetime for the electrons was confirmed after the afterglow decay curve simulation. Based on the analysis of thermally stimulated luminescence (TSL), the difference in afterglow was attributed to the different trap concentrations induced by the Dy3+ (Eu3+) doping in the Sr2B5O9Cl matrix.