Anti-thermal quenching behavior of Sm3+ doped SrMoO4 phosphor for new application in temperature sensing

SrMoO4: Sm3+ orange red-emitting phosphors for novel application in temperature measurement were prepared by solid-phase synthesis method. SrMoO4: Sm3+ phosphor with scheelite structure was assigned to tetragonal system and I41/a space group. Sm3+ ions could occupy Sr2+ lattice sites of SrMoO4. SrMoO4: Sm3+ consisted of irregular microparticle with well-crystallized pomegranate seed-like morphology and Sm3+ ions can be evenly distributed in the SrMoO4 matrix. The band gap value of SrMoO4: 1.0%Sm3+ (~4.228 eV) is less than that of SrMoO4 (~4.267 eV), which is due to generation of defective energy levels in band gap. The appropriate quenching concentration of Sm3+ was 1.0%, the critical distance is ∼25.57Å and θ is 7.1, close to 8, which was attributed to dipole−quadrupole interaction type of electric multipolar interaction. SrMoO4:1.0 %Sm3+ had excellent thermal stability of the PL peak at 598 nm and 644 nm and anti-thermal quenching property of the PL peak at 530 nm and 563 nm. The activation energy based on the intensity of the PL peak at 598 nm is 0.318 eV. The new dual-model thermometry strategy base on exponential function and modified Boltzmann population distribution would be proposed. SrMoO4:Sm3+ phosphor had the absolute sensitivities of 0.108 K-1 based on exponential function and the relative sensitivities of 0.601% K-1 based on modified Boltzmann population distribution. The excellent anti-thermal quenching and good thermal stability of SrMoO4: Sm3+ phosphors indicate that it has a potential for applications as pc-WLEDs and optical thermometry.