Pr3+-Doped β-NaYF4 for Temperature Sensing with Fluorescence Intensity Ratio Technique

Pure beta-NaYF4:0.8%Pr3+ powder sample was synthesized by the hydrothermal method. The temperature dependence of the fluorescence intensity ratio (FIR) of emission bands corresponding to the P-3(1) -> H-3(5) and P-3(0) -> H-3(5) transitions was measured in the temperature range of 120 K to 300 K excited by a 473 nm continuous wave (CW) laser. The dependence of the FIR on temperature is well fitted with an exponential function and the effective energy difference obtained is 457 cm 1, which gives further an absolute temperature sensitivity of 0.01352 K-1 at 300 K. The monotonous increase of FIR with temperature and high absolute temperature sensitivity demonstrate that this material can be used as temperature sensor. In addition, mono-dispersed NaYF4:1%Pr3+ nanoparticles were also synthesized.