Structural, thermal, and optical spectroscopic studies of Sm3+-doped Ba2ZnSi2O7 phosphors for optical thermometry applications

Samarium-doped Ba2ZnSi2O7 orange red-emitting phosphors for novel applications in temperature measurement were prepared by a solid-state synthesis method. A Ba2ZnSi2O7 akermanite-structured Sm3+ phosphor was allocated to the C2/c space group and monoclinic system. Using FTIR, identification of different bonds with their vibrational modes has been done. Stimulated at 403 nm, the as-prepared phosphors show yellow (560 nm), orange (600 and 645 nm), and red (705 nm) emissions, which were also used to maximize the dopant concentration. Sm3+ ions may be uniformly dispersed throughout the Ba2ZnSi2O7 matrix, and Sm3+ consists of irregular microparticles. Optical energy bandgap values for Ba2ZnSi2O7 and 0.4 mol%Sm3+ (similar to 3.33 eV and similar to 3.40 eV) reveal the formation of faulty energy levels in the band gap. Sm3+ quenching at an appropriate concentration of 0.4 mol%, with a critical distance of approximately 44.33 & Aring;, and a theta value of 3.93, almost equal to 4, was found to be indicative of the dipole-dipole type of electric multipolar interaction. Excellent thermal stability of the PL peaks was observed in Ba2ZnSi2O7:0.4%Sm3+. A novel dual-model thermometry approach based on an adjusted Boltzmann population distribution and an exponential function would be put forward. The Ba2ZnSi2O7:Sm3+ phosphor exhibited relative sensitivities of 2.02% K-1 based on modified Boltzmann population distribution through the FIR strategy and temperature-dependent lifetime was also employed to calculate relative sensitivities of 3.25% K-1 based on exponential function. In light of these experimental results, the produced Sm3+ doped Ba2ZnSi2O7 phosphors can thus be a promising choice for UV-excitable warm lighting systems and non-contact optical thermometry measurements.