Luminescence and optical thermometry strategy based on emission and excitation spectra of Pr3+ doped SrMoO4 phosphors

Recent developments of luminescence ratiometric thermometry have attracted much attention owing to its merits of fast response, non-invasiveness and high spatial resolution. In this work, the synthesis, crystal structure and luminescence properties has been carried out for Pr3+-activated SrMoO4 phosphors as optical thermometry. The XRD results show that all the phosphors possess the scheelite type tetragonal structure with space group I4(1)/a. The efficient luminescence of Pr3+ can be observed under intra-configurational (4f-4f) and charge transfer band (Mo-O) excitations, respectively. Upon different excitations, the quenching concentration of Pr3+ is diverse due to the multi-phonon relaxation and cross-relaxation processes occurring in different excited states of Pr3+ ions. The fluorescence intensity ratio (FIR) techniques based on emissions of P-3(0) and D-1(2) excited states of Pr3+, and the FIR in the excitations of the charge transfer band (Mo-O) and 4f-4f transitions of Pr3+ were employed for the thermometric characterizations in the 298-498 K range. Both results show remarkable performance in temperature sensing with the maximum relative sensitivity of 0.45%K-1@489 K and 0.98 %K-1@298 K, respectively. Our study demonstrates that Pr3+-activated SrMoO4 phosphors have a promising potential appli-cation in non-contact optical thermometry.