Tm²⁺ Activated SrB₄O₇ Bifunctional Sensor of Temperature and Pressure—Highly Sensitive, Multi‐Parameter Luminescence Thermometry and Manometry

Abstract

Noninvasive sensing of temperature and pressure offers new and exciting opportunities to investigate and monitor the variation of physicochemical and spectroscopic properties of materials under extreme conditions. In this work, Tm2+‐doped SrB4O7 phosphor material—a novel, contactless bifunctional, and multimodal optical sensor for pressure and temperature is reported. A series of SrB4O7: xTm2+ samples are synthesized via a high‐temperature solid‐state method in air. The impact of high pressure (up to ≈13 GPa) and temperature (from 10 to 400 K) on spectroscopic properties of SrB4O7:Tm2+ is investigated. The emission band of Tm2+ demonstrates a significant spectral shift and a band broadening as a function of both pressure and temperature. Such a result is a consequence of a significant change of vibronic components of the Tm2+ 4f125d ↔ 4f13 zero‐phonon line. The emission bandwidth and its spectral position exhibit excellent sensitivities to pressure, that is, ≈23.17 and ≈−11.85 cm−1 GPa−1, respectively. Furthermore, for the first time, it is shown that temperature sensing can be realized via four different pathways in a single material: i) bandwidth, ii) band shift, iii) band intensity ratio, and iv) luminescence lifetime, with maximal sensitivities of ≈3.85 cm−1 K−1, 1.44 cm−1 K−1, 1.48% K−1 and 4.16% K−1, respectively.

How to calibrate luminescent crossover thermometers: a note on “quasi”-Boltzmann systems

“…This transition has also been considered a potential alternative for optical pressure sensing of the narrow R emission lines of Cr 3+ in ruby (Al 2 O 3 :Cr 3+ ). 36,39…”

“…This transition has also been considered a potential alternative for optical pressure sensing of the narrow R emission lines of Cr 3+ in ruby (Al 2 O 3 :Cr 3+ ). 36,39 The high intensity of the 5 D 0 -7 F 0 transition of Sm 2+ is not readily explicable within the framework of Judd-Ofelt intensity theory of the 4f n -4f n transitions but can be well-understood with the Wybourne-Downer mechanism instead. [40][41][42][43] It is attributed to the high intensity of the induced electric dipole character to the 5 D 0 -7 F 0 transition mediated by a spin-orbit interaction between the 4f 6 and 4f 5 5d 1 levels of Sm 2+ , which is a third-order perturbative effect only.…”

Eu2+ emission from thermally coupled levels – new frontiers for ultrasensitive luminescence thermometry

“…8 Recently, we have presented the benefits of applying the 5d -4f emissions of Pr 3+ and Tm 2+ in luminescence thermometry, showing that the use of their inter-configurational transitions greatly enhances the relative thermal sensitivity of such thermometers. [20][21][22][23][24] Now, we turn our attention to the Eu 2+ luminescence and its possible utility in the optical determination of temperature. The emission intensity of this ion is often strong, due to the broadband parity-allowed 4f -5d excitation transition, that can be easily realized using standard light sources, which also widens the variety of potential applications.…”

Tunable broadband photoluminescence from bismuth‐doped calcium aluminum germanate glasses prepared in oxidizing atmosphere

“…With the addition of GeO 2 (with a higher molecular weight of 104.64 g/mol, relative to Al 2 O 3 [101.96 g/mol] and CaO [56.08 g/mol]), the mass density of the glasses gradually increases from ∼2.91 g/cm 3 for the GeO 2 -free glass to ∼3.63 g/cm 3 for 40 mol% GeO 2 ; for higher degrees of substitution, only minor changes in mass density are observed (Figure 3A). The opposite trends are seen for the sound wave velocities and elastic properties.…”

“…Materials that exhibit tunable and broadband photoluminescence (PL) are of great interest for customized visible-to-infrared light sources and spectral converters, for example, for highly sensitive temperature sensing, highdensity optical communication, photodynamic therapy, or photochemical energy conversion. [1][2][3][4][5][6] Such converter materials rely on the combination of a robust matrix phase with one or more suitable activator species. When glasses are used for this purpose, the activator can be homogeneously incorporated into the material, which avoids light scattering at particle-matrix interfaces.…”