Dual-luminescent Sc2(MoO4)3:Dy3+/Eu3+ phosphor system: energy transfer dynamics and high-sensitivity temperature sensing

Abstract

A series of Dy³⁺/Eu³⁺ co-doped Sc₂(MoO₄)₃ (SMO) phosphors were synthesized via a conventional solid-state reaction. Phase purity and morphology were characterized by X-ray diffraction with Rietveld refinement and scanning electron microscopy, confirming the formation of phase-pure orthorhombic crystals. The electronic structure was investigated through density functional theory calculations combined with diffuse reflectance spectroscopy. Under 266 and 352 nm excitation, the Dy³⁺ doped SMO phosphors exhibited characteristic emission peaks at 488 nm (⁴F_9/2 → ⁶H_15/2), 578 nm (⁴F_9/2 → ⁶H_13/2), 667 nm (⁴F_9/2 → ⁶H_11/2), and 761 nm (⁴F_9/2 → ⁶H_9/2). In the Dy³⁺/Eu³⁺ co-doped systems, detailed analysis of spectra and luminescence decay kinetics quantitatively confirmed efficient energy transfer from Dy³⁺ to Eu³⁺. Finally, the optimized SMO:Dy³⁺, Eu³⁺ phosphors achieved maximum relative (S_r) and absolute (S_a) sensitivities of 3.817% K⁻¹ and 0.018 K⁻¹, respectively, demonstrating potential for ratiometric optical thermometry applications.