Optical tunability and higher order polynomial parameterization of the temperature dependent emission in Sm3+/Eu3+ co-activated tungstate phosphors for optoelectronic applications

Phosphor based colour-tunable materials and optical temperature sensors have attracted considerable attention due to their non-contact temperature detection capabilities and optoelectronic applications. In this work, Ca 2 MgWO 6 :1.25 mol% Sm 3+ , xEu 3+ (x = 0-16 mol%) phosphors were synthesized via a solid-state reaction route. Under 409 nm excitation, efficient energy transfer from Sm 3+ to Eu 3+ ions enabled strong spectral tunability, with an optimal Eu 3+ concentration of 10 mol% beyond which concentration quenching occurred through dipole-quadrupole interactions. The optimized phosphor showed a direct optical band gap of 3.34 eV and retained 47% of its emission intensity at 498 K, indicating high thermal stability. The activation energy (0.21 eV) and quenching temperature (393 K) confirmed excellent thermal robustness. Temperature-dependent luminescence analysis using a 4 th order polynomial fit yielded maximum absolute and relative sensitivities of 0.0432 K -1 and 0.29% K -1 at 298 K, demonstrating strong potential for solid-state lighting and optical temperature sensing applications. • CMW: Sm 3+ , Eu 3+ phosphors were synthesized using solid-state reaction method. • Under 409 nm excitation, Sm 3+ → Eu 3+ energy transfer enabled spectral tunability. • The optimized phosphor exhibited a activation energy of 3.34 eV. • Phosphor retained 47% of its initial emission intensity at 498 K. • Phosphor showed relative sensitivity of 0.29 % K -1 at 298 K.