Luminescence characteristics and low temperature optical temperature measurement of Pr ³⁺ doped Sr ₂ NaMg ₂ V ₃ O ₁₂ phosphors

A series of Pr³⁺-doped Sr₂NaMg₂V₃O₁₂ (SNMV) garnet phosphors were successfully synthesized by a high temperature solid-state method. The crystal structure, luminescence properties and temperature sensing properties of the phosphors were systematically studied. Under excitation at 339 nm, SNMV:Pr³⁺ phosphors exhibit strong blue-green broadband emission in the wavelength range of 400-700 nm and typical red emissions of Pr³⁺ at 612 nm and 624 nm, which correspond to the energy level transition of the [VO₄]^3- group and the ¹D₂ → ³H₄,₅ transition of Pr³⁺, respectively. Furthermore, in the temperature range of 98-298 K, high sensitivity optical temperature sensing is realized based on the fluorescence intensity ratio (FIR) and the fluorescence lifetime (FL). In FIR mode, the maximum absolute sensitivity (<i>S</i>_a) and relative sensitivity (<i>S</i>_r) of the phosphor are 0.01782 K^-1 (298 K) and 1.13543% K^-1 (298 K), respectively. In FL mode, the maximum <i>S</i>_a and <i>S</i>_r values are 0.0889 K^-1 (198 K) and 0.62752% K^-1 (223 K), respectively. The results show that SNMV:Pr³⁺ phosphors have great potential in the field of optical temperature measurement.