Energy transfer in Ce and Eu co-doped barium thiogallate: A photoluminescence characterization

Abstract

In this work we report for the first time the fluorescence properties of Ce 3+ single-doped and Ce 3+/Eu 2+ co-doped BaGa 2S 4 crystals, studied by means of time resolved measurements. The single-doped samples fluorescence was characterized by the Ce 3+ radiative transitions from the 2D level to the 2F 5/2 and 2F 7/2 levels with a lifetime of 18 ns, and by a radiative transition from the E g level to the ground state of Ce 3+ ions with a lifetime of 11 ns. The co-doped samples fluorescence was characterized by Eu 2+ radiative transition from 4f 6d state to the ground state with a lifetime of 290 ns. Ce 3+ emissions in co-doped samples are strongly quenched and a lifetime of 6 ns is observed. The reported data are discussed in the framework of energy transfer process between Ce and Eu. The rate of the energy transfer was estimated in 7.5 × 10 7 s −1 with efficiency of 66%.