关键词: photoluminescence, Sc₂W₃O₁₂:Eu³⁺, negative lattice expansion, thermal-enhanced luminescence

Abstract: Recently, lanthanide-ion-doped luminescent materials have been extensively used as optical thermometry probes due to their fast responses, non-contact, and high sensitivity properties. Based on different responses of two emissions to temperature, the fluorescence intensity ratio (FIR) technique can be used to estimate the sensitivities for assessing the optical thermometry performances. In this study, we introduce different doping concentrations of Eu$^{3+}$ ions into negative thermal expansion material Sc$_{2}$W$_{3}$O$_{12}$ to increase the thermal-enhanced luminescence from 373 K to 548 K, and investigate the temperature sensing properties in detail. All samples can exhibit their good luminescence behaviors thermally enhanced. The emission intensity of Sc$_{2}$W$_{3}$O$_{12}$:6-mol% Eu$^{3+}$ phosphor reaches 147.8% of initial intensity at 473 K. As the Eu$^{3+}$ doping concentration increases, the resistance of the sample to thermal quenching decreases. The FIR technique based on each of the transitions $^{5}$D$\to {}^{7}$F$_{1}$ (592 nm) and $^{5}$D$\to ^{7}$F$_{2 }$ (613 nm) of Eu$^{3+}$ ions demonstrates a maximum relative temperature sensitivity of 3.063% K$^{-1}$ at 298 K for Sc$_{2}$W$_{3}$O$_{12}$:6-mol% Eu$^{3+}$ phosphor. The sensitivity of sample decreases with the increase of Eu$^{3+}$ concentration. Benefiting from the thermal-enhanced luminescence performance and good temperature sensing properties, the Sc$_{2}$W$_{3}$O$_{12}$:Eu$^{3+}$ phosphors can be used as optical thermometers.

Key words: photoluminescence, Sc₂W₃O₁₂:Eu³⁺, negative lattice expansion, thermal-enhanced luminescence