Color-tunable binary solid-solution phosphor, (Sr3SiO5)1− x (Sr3AlO4F) x , for white LEDs: Energy transfer mechanism between Ce3+ and Tb3+

Abstract: The possibility of using a solid solution as a light convertor in white LEDs was studied. A solid solution of Sr3AlO4F and Sr3SiO5 was prepared by solid-state reaction and was activated with Ce3+. Phosphor exhibits an asymmetric yellow–orange emission band which is broadened and red-shifted when coactivated with Tb3+. Decay profile analysis using the Inokuti–Hirayama model revealed that the mechanism involved was electric dipole–quadrupole interaction. The critical distance was calculated from concentration quenching data, multipolar interaction, and exchange interaction. The thermal stability of photoluminescence was investigated by assuming an Arrhenius temperature dependence, and the activation energy for thermal quenching was calculated. When analyzed in combination with an InGaN LED, the phosphor exhibited high color-rendering index and excellent correlated color temperature. These results demonstrate that this solid solution phosphor with its superior properties is highly suitable for use in white LEDs. [Copyright &y& Elsevier]