High temperature measurement using luminescence of Pr³⁺ doped YAG and Ho³⁺ doped CaF₂

Abstract

Calibration plots have been developed for temperature sensing by measuring luminescence from Pr3+ doped YAG and Ho3+ doped CaF2. 1D2 lifetime of Pr3+ doped YAG decreased linearly from 187 μs to 110 μs as the sample temperature was changed from 20 °C to 1000 °C. 5F5 lifetime of Ho3+ doped CaF2 varied linearly from 380 μs to 188 μs as the sample temperature was changed from 20 °C to 1000 °C. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Physical Background for Luminescence Thermometry Sensors Based on Pr3+:LaF3 Crystalline Particles

“…demonstrates strong luminescence lifetime dependence on temperature as it is shown in [21]. For the system Pr 3+ :YAG the measured lifetime of 1 D 2 decreases linearly from ∼190 s at 0 ∘ C to ∼110 s at 1000 ∘ C. From another side, the thermal sensing materials based on Pr 3+ ions attract great attention of the scientific community because of its thermal sensitivity in broad temperature range [12,23] and biomedical potential [24].…”

“…The luminescent spectra have the emissions bands at about 487, 523, 537, 580, 601, and 672 nm which are interpreted as a result of the transition from the 3 P ( = 0, 1, 2) excited states which is 2 times less than one for YAG (700-865 cm −1 ). Indeed to bridge the 3 P 0 -1 D 2 energy gap, the 9 phonons are required in case of LaF 3 and only 4 or 5 ones for YAG; thus, the multiphonon relaxation is expected negligible [21,30]. Moreover, the electron phonon coupling constants of YAG are highly different from those of LaF 3 [21].…”

“…Indeed to bridge the 3 P 0 -1 D 2 energy gap, the 9 phonons are required in case of LaF 3 and only 4 or 5 ones for YAG; thus, the multiphonon relaxation is expected negligible [21,30]. Moreover, the electron phonon coupling constants of YAG are highly different from those of LaF 3 [21].…”

“…For example, the active-core/active-shell Nd 3+ /Yb 3+ -doped LaF 3 NPs demonstrate relative thermal sensitivity around 0.41 ± 0.01% ⋅ ∘ C −1 , at 10 ∘ C [9,11]. The systems based on Pr 3+ are studied in [19][20][21]. In case of Pr 3+ ions, the energy gap between 3 P 0 and the next-highest state, 3 P 1 , is only a few hundred cm −1 for most host matrixes (for example, for LaF 3 [22] and CsCdBr 3 [22] it is around 500 cm −1 ), 3 P 1 becomes thermally populated following 3 P 0 excitation, and the luminescence spectrum contains both 3 P 0 and 3 P 1 emission, with intensity ratios consistent with the predicted Boltzmann distribution among these states [22].…”

Temperature dependence of 3P0 Pr3+ fluorescence dynamics in Y4Al2O9 crystals

“…Since such processes in phosphor materials often occur via thermal activation, understanding them is vital to elucidate the luminescence mechanisms. In addition, as it was recently demonstrated, the temperature dependence of the Pr 3? fluorescence features can be used to measure temperature [8][9][10] and is interesting from the application point of view in optical thermometry.…”