Study on optical temperature sensing properties of β-NaYF4:Tm3+/Yb3+ nanoparticles

Abstract

As an optical temperature sensor, rare earth ions (Tm3+/Yb3+) co-doped β-NaYF4 upconversion nanoparticles (UCNPs) were synthesized via a thermal decomposition method. Fluorescence intensity ratio (FIR) between the 700 nm (3F2,3→3H6) and 800 nm (3H4→3H6) corresponding to the emission spectra of Tm3+ was studied in the temperature range of 300–498 K under 980 nm excitation as a function of optical thermometry. It was found that the temperature sensing sensitivity of Tm3+/Yb3+ co-doped β-NaYF4 UCNPs was higher than that of other rare-earth doped materials which were reported previously by using FIR technique in terms of sensitivity. β-NaYF4:Tm3+/Yb3+ UCNPs were promising to be a temperature sensor with the high sensitivity and resolution, especially with the superior property of well separated emission bands (700 nm and 800 nm).