Ca3La6Si6O24:Eu3+ orange-red-emitting phosphor: Synthesis, structure and luminescence properties

Ca3La6Si6O24:Eu3+ phosphors are synthesized in air through high-temperature solid-state reaction method. The crystal structure, morphology, and luminescence properties are investigated. Ca3La6Si6O24:Eu3+ phosphor emits orange-red light in the range of 570-750 nm due to the D-5(0) -> F-7(S) (S = 0, 1, 2, 3, and 4) transitions of Eu3+ ion. The optimal Eu3+ doping concentration is similar to 8 mol%. The energy transfer mechanism is the electric multipolar interactions. The luminescence lifetimes are similar to 1.70, 1.66, 1.62, 1.57, 1.51, and 1.49 ms for x = 2, 4, 6, 8, 10, and 12 mol%, respectively. Ca3La6Si6O24:Eu3+ phosphor shows excellent thermal stability with the E-a value similar to 0.3314 eV. The luminous and temperature quenching mechanisms are explained by the energy level diagram and configurational coordinate diagram of Eu3+ ions, respectively. The experimental results indicate that Ca3La6Si6O24:Eu3+ phosphor has a potential application in white light-emitting diodes (LEDs) based on the near UV (394 nm) LED chip.