Temperature dependent luminescence of Dy3+ doped BaYF5 nanoparticles for optical thermometry

Dy³⁺ doped BaYF₅ nanoparticles with tetragonal structure were synthesized by hydrothermal method and solvothermal method. The structural and the luminescent properties of the samples were characterized by X-ray diffraction pattern, TEM and photoluminescence spectra. Emission of Dy³⁺ originated from ⁴I_15/2 located at 450 nm and ⁴F_9/2 located at 478 nm, 573 nm and 660 nm were observed under excitation of 355 nm laser. Behavior of fluorescence intensity ratio with temperature increasing from room temperature to approximately 800 K was investigated. And the optimum temperature range for thermometry is obtained to be 550–800 K according to its sensitivity-temperature relation, indicating the potential application of BaYF₅:Dy³⁺ as a luminescent temperature sensor.