Thermometric properties of SrMoO4:Tb3+ phosphor based on redshift of charge transfer band edge

Abstract

In this study, SrMoO4:Tb3+ phosphors were successfully synthesized for a single-band ratiometric (SBR) thermometry utilizing the redshift of CTB. The SrMoO4:Tb3+ phosphors have a tetragonal system owing to I41/a space group and irregular microparticles possessing a mean size of 20 μm. The incorporation of Tb3+ ions into the SrMoO4 matrix lattice leads to a reduction in the bandgap energy owing to occurrence of defects level in gap-band. Thermal quenching concentration of Tb3+ is 1%, due to the dipole-dipole interaction between Tb3+ and Tb3+ ions. This study observed an interesting redshift in the edge of the CTB with increasing temperature, which can be explained using the configurational coordinate diagram. This phenomenon can be utilized to construct this SBR temperature measurement strategy by selecting appropriate excitation peaks or bands with different thermal responses. The study also demonstrated that SrMoO4: 1%Tb3+ has higher Sa value of 13.31 × 10−2 K−1 @573 K and Sr value of 3.54 K-1@298 K in optical thermometry, making it a suitable candidate for optical temperature measurement.