Reassessing the luminescent persistent of phosphate-based host for tunable red-afterglow

Red Luminescent Persistent oxide materials are not reported in literature with high efficiency. Depending on the emitting ion or host matrix, they either absorb in the blue-green region or emit in these same regions, hindering chromaticity coding of color-coded photonic devices. Thus, the objective of this work was to study the luminescent properties of Ca₃(PO₄)₂ (CPO) doped with Mn²⁺/Eu²⁺/Dy³⁺, Mn²⁺/Dy³⁺ and Eu²⁺/Dy³⁺ to evaluate the potential as an efficient and adjustable red afterglow material. XRD confirmed that α, β, and α, β CPO phase was obtained, respectively. All three compositions showed absorption in the same region (260 nm) and broad emission between in 400-550 nm, with the presence of the characteristic bands of Eu³⁺. Furthermore, while the literature reports a persistent red emission at ~660 nm for CPO:Mn²⁺/Dy³, our findings highlight significant reproducibility issues regarding this optical behavior, emphasizing the need for further structural and optical optimization in future studies.