Spectroscopic and thermal behavior of ca₈ MgLa(PO₄)₇:Eu²⁺,Mn²⁺ phosphor powders and polymer composites

Inorganic phosphates doped with rare-earth and transition-metal ions are of great interest due to their tunable optical properties and potential in white-light-emitting applications. In this study, Ca₈MgLa(PO₄)₇ phosphors co-doped with Eu²⁺ and Mn²⁺ ions were synthesized via the solid-state reaction method and comprehensively characterized by structural and spectroscopic techniques. Phase-pure samples with different activator ratios were analyzed to elucidate the correlation between composition, local coordination environment, and photoluminescence behavior. Detailed temperature-dependent emission studies revealed pronounced spectral evolution associated with thermally activated redistribution of Eu²⁺ emission among crystallographically distinct sites, as well as with host lattice expansion. The observed changes are discussed in terms of energy transfer and electron-phonon coupling mechanisms responsible for broadband emission and thermal quenching. To evaluate the application potential, the compound was mixed with a relevant polymer to produce a composite, which was then characterized spectrally. Additionally, a simulation of its performance under industrial conditions was carried out. Results showed that after 2000 h of aging tests, the quantum efficiency of Ca₈MgLa(PO₄)₇:1 %Eu²⁺:10 %Mn²⁺ remained stable, with a 10 % increase in luminescence intensity.