In this study, it is shown how the temperature range of luminescent thermometers can be widened in an unprecedented way by combining the intra‐ and interconfigurational transitions of the Pr3+ ion in a single material. Using Sr2GeO4:Pr3+ crystalline powders as an illustrative example, the implementation of luminescence thermometry is reported in the broadest temperature range up to now (17–600 K) with a remarkable performance: maximum relative sensitivity values of 9.0% · K−1 (at 22 K, cryogenic range), 0.6% · K−1 (at 300 K, physiological range), and 0.5% · K−1 (at 600 K, high‐temperature range) and minimum temperature uncertainty of 0.1 K.

Bandgap engineering allows tuning the performance of a dual-mode luminescence thermometer in the 17–700 K range of temperature.

Having proven that the temperature range of luminescent thermometers can be greatly widened by combining the intra‐ and interconfigurational transitions of the Pr3+, the possibility to manage important thermometric parameters by bandgap engineering and variation of energy of excitation photons are examined. Partial replacement of Ge with Si to form Sr2(Ge,Si)O4:Pr is very useful to manage these luminescence thermometer properties. This allows control of the range of temperatures within which the 5d1→4f Pr3+ luminescence can be detected. Also, excitation energy appears to affect the thermometer's performance. These allow adjustment of the range of temperatures that can be measured with the highest accuracy, reaching the spectacular value of Sr = 9.2% K−1 at 65 K for a Sr2(Ge0.75,Si0.25)O4:0.05%Pr3+ thermometer upon 244 nm excitation. For the first time, it has been proven that excitation energy may significantly affect the performance of luminescence thermometers. In Sr2(Ge0.75,Si0.25)O4:0.05%Pr3+ the highest relative sensitivity shifts from 65 K upon 244 nm excitation (Sr = 9.2% K−1) to 191 K upon 253 nm excitation (Sr = 3.97% K−1). This occurs despite both excitation wavelengths fitting within the 4f→5d1 excitation band. This paper shows that bandgap management is useful to effectively design new luminescent thermometers.

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.

of high sensitivity has become a continuously more important and challenging task, as increasing demand for both industrial development and various scientific research purposes. However, the conventional thermometers based on the expansion of liquids or metals, such as mercurial thermometer, thermocouples or pyrometers suffer from several shortages, such as: limited spatial resolution (inability to detect the temperature of an object with the scale below 10 µm), often necessity of physical contact, low sensitivity, and so forth. [2] Recently, the remote thermo-vision (thermal imaging) technique at nano-or micro-scale has been attracting increasing interest of the researchers and industry. This imaging technique has been more frequently used, since it allows immediate temperature readouts and thermal mapping in biological systems (in vivo), which is also beneficial for preventing damage of the biological, mechanical or electronic components. [3][4][5] Luminescence thermometry, as an alternative to the thermo-vision technique, provides the opportunity to also detect temperature in a non-invasive way, with higher sensitivity, better spatial resolution and rapid response. However, new routes of designing novel luminescent thermometers are required to overcome the existing technical drawbacks and to improve the temperature sensing performance.The concept of optical temperature sensing using band intensity ratio is considered as one of the most effective, self-reference, non-invasive, and rapid detection techniques for the local temperature in natural or engineered systems. In this work, for the first time a divalent lanthanide-co-doped dual-center system, i.e., SrB 4 O 7 :Eu 2+ /Sm 2+ phosphors, working as a bifunctional ratiometric sensor of temperature and pressure is employed. With temperature alterations, the Eu 2+ /Sm 2+ luminescence intensity ratio and the emission lifetime of Sm 2+ are significantly changed, showing unprecedentedly high relative sensitivity of 45.6 and 3.17% K -1 , respectively. Moreover, in the pressure range from ≈10 to 40 GPa, the intensity ratio of the Eu 2+ /Sm 2+ emissions shows strong pressure dependence and can be utilized for pressure monitoring, with high pressure relative sensitivity of ≈13.8% GPa -1 . The superior performance indicates that the developed dual-center Eu 2+ /Sm 2+ -codoped SrB 4 O 7 phosphors are promising candidates for supersensitive optical sensing applications. The findings open a new approach of designing optical temperature and pressure sensors.