Energy transfer relation of a novel Ce³⁺/Pr³⁺/Eu³⁺ co-doped Sr_2.975-xLa_xAlO_4+xF_1-x solid solution phosphor

The photoluminescence properties and energy transfer of a new Ce³⁺/Pr³⁺/Eu³⁺ co-doped solid-solution composition of Sr_2.975-xLa_xAlO_4+xF_1-x (LSAF) phosphor are investigated. Upon doping Pr³⁺ into lattices of LSAF:Ce host, a shoulder emission peak is observed at about 620 nm, owing to the transition of ¹D₂→³H₄. Addition of Eu³⁺ to LSAF:Ce³⁺, Pr³⁺ phosphor results in a sharp emission peaked at 675 nm for the ⁵D₀→⁷F₃ transition and an increase of the intensity of red emission for Pr³⁺ with increasing Eu³⁺ concentration. The pathways of energy transfer among Ce³⁺, Pr³⁺, and Eu³⁺ are proposed to be responsible for color addition of a red component to the primary yellow emission, enabling a potential adjustable color for blue excitable warm white.