Pr3+-doped NaY(MoO4)2 phosphor for optical thermometry applications

Abstract

The Pr3+-doped NaY(MoO4)2 crystals were prepared by the hydrothermal method, and sodium citrate was used as the chelating agent. The structure, morphology, and relationship between optical properties and temperature were measured. The X-ray diffraction results showed that the crystal structure is body-centered tetragonal, and the addition of sodium citrate did not distinctly alter the phosphor structure. From 298 to 483 K, under a 270 nm excitation, 1D2-3H4, 3P0-3H4, and 3P0-3F2 transitions have different temperature dependencies, and two groups of fluorescence intensity ratio (1D2-3H4 and 3P0-3H4, 1D2-3H4 and 3P0-3F2) can be defined to characterize the temperature. The morphological characteristics of the sample were obtained by the detection of field emission scanning electron microscope. The experiment showed that the relative sensitivity changed as a function of the sample morphology. The maximum relative sensitivity of the synthesized phosphors (Cit3−/Re3+ = 2) reached 1.00% K−1 at 313 K, and the relative sensitivity remained near the maximum value when the temperature was close to human body temperature (308–315 K). The Pr3+-doped NaY(MoO4)2 phosphor is a high-performance material that can be employed for refined calibration and temperature measurements according to the two-group schema defined by fluorescence intensity ratio. Thus, it show utilization potentiality in self-calibration optical thermometers and temperature measurements including humans and special environment.