Sol-gel assisted optical and structural studies of Dy 3+ /Eu 3+ Co-doped NaLa(MoO 4 ) 2 phosphor via energy transfer mechanism

Dy3+- and Eu3+-activated as well as Dy3+–Eu3+ co-doped NaLa(MoO4)2 phosphors were synthesized by a sol–gel method and systematically studied to establish correlations between structural characteristics and luminescent performance, with emphasis on inter-ionic energy transfer. X-ray diffraction coupled with Rietveld refinement confirmed the formation of a single-phase scheelite-type structure, indicating effective incorporation of rare-earth ions into the host lattice. Structural stability of the molybdate framework was supported by FTIR analysis, while scanning electron microscopy revealed agglomerated particles consisting of well-crystallized grains. Photoluminescence studies showed strong visible emission with concentration-dependent quenching at higher dopant levels. In co-doped compositions, progressive suppression of Dy3+ emission accompanied by enhancement of Eu3+ red emission indicated efficient non-radiative energy transfer governed by multipolar interactions. Chromaticity analysis demonstrated tunable emission spanning near-white to warm red regions with a broad range of correlated color temperatures, highlighting the suitability of Dy3+–Eu3+ co-activated NaLa(MoO4)2 phosphors for solid-state lighting applications.