Photoluminescence properties of Ce³⁺ and Mn²⁺-activated Ba₉Sc₂Si₆O₂₄ phosphor for white light emitting diodes

A single-phased silicate compound (Ba_1-xCe_x)₉₍Sc_1-yMn_y)₂Si₆O₂₄ was prepared by solid-state reaction at high temperature. From powder X-ray diffraction (XRD) analysis, the formation of Ba₉Sc₂Si₆O₂₄ with R3 space group was confirmed. In the photoluminescence spectra under ultraviolet (UV) ray excitation, the Ba₉Sc₂Si₆O₂₄:Ce³⁺, Mn²⁺ phosphor emits two distinctive color light bands: a blue one originating from Ce³⁺ and a red one caused by Mn²⁺. The energy transfer process from Ce³⁺ to Mn²⁺ was confirmed, the critical radius as well as the transfer efficiency was calculated, and the energy transfer mechanism was discussed. In addition, the decay-time testing indicates that the energy transfer efficiencies from Ce(1) to Mn²⁺ and Ce(2) to Mn²⁺ are different. The emission chromaticity of Ba₉Sc₂Si₆O₂₄:Ce³⁺, Mn²⁺ phosphor could be tuned from blue to red by altering the Ce³⁺/Mn²⁺ concentration ratio.