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

Abstract

The main goal of this study was creating multifunctional nanoparticles based on rare-earth doped LaF 3 nanocrystals, which can be used as fluorescence thermal sensors operating over the 80-320 K temperature range including physiological temperature range (10-50 ∘ C). The Pr 3+ :LaF 3 ( Pr = 1%) microcrystalline powder and the Pr 3+ :LaF 3 ( Pr = 12%, 20%) nanoparticles were studied. It was proved that all the samples were capable of thermal sensing into the temperature range from 80 to 320 K. It was revealed that the mechanisms of temperature sensitivity for the microcrystalline powder and the nanoparticles are different. In the powder, the 3 P 1 and 3 P 0 states of Pr 3+ ion share their electronic populations according to the Boltzmann and thermalization of the 3 P 1 state takes place. In the nanoparticles, two temperature dependent mechanisms were suggested: energy migration within 3 P 0 state in the temperature range from 80 K to 200 K followed by quenching of 3 P 0 state by OH groups at higher temperatures. The values of the relative sensitivities for the Pr 3+ :LaF 3 ( Pr = 1%) microcrystalline powder and the Pr 3+ :LaF 3 ( Pr = 12%, 20%) nanoparticles into the physiological temperature range (at 45 ∘ C) were 1, 0.5, and 0.3% ∘ C −1 , respectively.

Ca1-x-yYbxPryF2+x+y solid solution powders as a promising materials for crystalline silicon solar energetics

“…In the visible spectral range, characteristic Table 1 is maintained across the whole paper for the reader's convenience. spectral lines of praseodymium ions have been resolved which agree with literature data [19] and consistent with data for other fluoride systems containing Pr 3+ [20][21][22]. These lines correspond to numerous transitions from 3 P J manifold to 3 H J and 3 F J manifolds.…”

Bandgap Engineering and Excitation Energy Alteration to Manage Luminescence Thermometer Performance. The Case of Sr2(Ge,Si)O4:Pr3+

“…By increasing the temperature, the lifetime is systematically shortened, and at 300 K the emission is not measurable. The activation energy E a = 0.15 eV of thermal quenching was calculated using the single‐barrier model described by Equation where p and τ are the rate of luminescence transition and its decay time at temperature ( T ), respectively, τ o is the radiative decay time of a given luminescence (when quenching is not present), B is a constant depending on the radiative and nonradiative decay rates, and k B is the Boltzmann constant (8.617 × 10 −5 eV K −1 ). Surprisingly, the obtained E a = 0.15 ± 0.01 eV does not differ from what was found previously for the Si‐free Sr 2 GeO 4 :Pr 3+ .…”

“…Also, impressive minimum temperature uncertainty down to δT = 0.1 K was achieved. Earlier, a number of compositions activated with Pr 3+ were examined as luminescence thermometers, but none of them presented outstanding performance. The Sr 2 GeO 4 :Pr 3+ benefitted greatly from using both intra‐ (mainly 3 P 0 → 3 H J and 1 D 2 → 3 H J ) and interconfigurational 5d→4f parity‐allowed transitions.…”

Peculiarities of luminescence decay of Ce:LaF3 nanoparticles depending on conditions of hydrothermal treatment

“…The nanoparticles of LaF3 doped with 12 % of Ce3+ ions were synthesized via coprecipitation method [3][4][5] and subsequent modification of prepared nanoparticles using the microwave-assisted hydrothermal treatment was performed [6]. Four samples collected at different stages of fabrication were investigated.…”

“…Due to low-energy phonons these materials provide advantages in up-conversion and photosensitizing demanding applications [1,2] and open novel applications for quantum electronics and photonics [3]. The variation of synthesis conditions which leads changes in energy transfer processes between impurities and influences the luminescence quenching factors [2] opens the way to manage characteristics of materials.…”