Tm3+,Yb3+: Y2SiO5 up-conversion phosphors: Exploration of temperature sensing performance by monitoring the luminescence emission

Abstract

Tm3+,Yb3+:Y2SiO5 ceramic powders synthesized via combustion route exhibited up-conversion (UC) fluorescence when were submitted to CW-laser radiation at 980 nm. Four emission bands at 478 nm, 650 nm 690 nm and 798 nm, corresponding to transitions 1G4→3H6, 1G4→3F4, 3F2,3 → 3H6 and 3H4→3H6 were observed. The properties of the UC emission bands are influenced by temperature. Thermal coupling levels (TCL) cause a noticeable change in the relative intensities between the excited states 3F2,3 → 3H6 and 3H4→3H6 in the temperature range of 298–473 K. The maximum absolute sensitivity (1.25 × 10−3 K-1, 473 K) and relative sensitivity (1.83% K−1, 298 K) were obtained using the fluorescence intensity ratio (FIR) technique. Thermal sensing performance has been explored by utilizing the FIR technique between non-thermally coupled levels (NTCL). Through the calculation of FIR of NTCL1G4→3H6 and 3H4→3H6, the value of the relative sensitivity was acquired (1.5% K−1, 298 K). The comparison of TCL and NTCL FIR-method performances shows that this ceramic powder has the potential to be used as a ratiometric thermal sensor for remote temperature measurements.