Supersensitive Ratiometric Thermometry and Manometry Based on Dual‐Emitting Centers in Eu²⁺/Sm²⁺‐Doped Strontium Tetraborate Phosphors

Abstract

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.

Temperature invariant lifetime based luminescent manometer on Mn4+ ions

“…Since the emission band of the Cr 3+ ions of Al 2 O 3 : Cr 3+ spectrally overlaps with the emission band of the analyzed SrGdAlO 4 : Mn 4+ , the spectral shift of the SrB 4 O 7 : Sm 2+ 5 D 0 → 7 F 0 emission line was used as a pressure indicator in the DAC. 30 The sample was placed in a ≈140 μm size hole drilled in a 250 μm thick stainless steel gasket. The methanol–ethanol solution (4 : 1 ratio) was used as a pressure transmission medium.…”

Evolution of the full energy structure of Mn4+in fluoride phosphors under high pressure conditions

“…The lowest obtained eigenvalue corresponds to the energy of the 2 E emitting state for given d and g. Finally, calculating 2 E -4 A 2 requires subtracting the energy of the ground state 4 A 2 (À15B); see eqn (17).…”

“…So far such phosphors have not been found; however, there have been several reports of luminescent pressure sensors for the GPa pressure ranges, encountered in high-pressure experimental settings. [15][16][17][18] Secondly, high pressure spectroscopy can be viewed as a powerful analytical tool that uncovers additional information about the spectroscopic properties of phosphors by examining pressure shifts in optical spectra, electronic level crossings or changes in the luminescence decay. 2,19 This is especially attractive, since there is a correspondence between the properties (e.g.…”

Thermochromic Upconversion Emission in Tm3+/Yb3+-Codoped La2Mo3O12 Microparticles via Negative Thermal Expansion Engineering for Ultrahigh Sensitivity Optical Thermometry

“…Compared with the conventional contacted thermometers, a lot of attention has been attracted by luminescence thermometers, which utilize temperature-associated fluorescence characteristics, such as fluorescence intensity ratio (FIR), band position, decay time, full width at half-maximum of emission band, etc., − of luminescent materials because of their advantages of rapid response, high accuracy/resolution, and contactless characteristic. , Particularly, by adopting the FIR technique, optical thermometry is extensively adopted, in which the temperature-related emission intensities of thermally coupled levels (TCLs) of rare-earth ions are investigated. , Fu et al revealed that the thermometric properties of rare-earth ions, which were based on their TCLs, can be adjusted by controlling the excitation wavelength and utilizing tridoping engineering. , However, the optical thermometers based on the TCLs of rare-earth ions possess low relative sensitivity ( S r ) triggered by the small energy band gap of TCLs (200 ≤ Δ E ≤ 2000 cm –1 ). , For the purpose of addressing this issue, researchers proposed a new route, namely, using the FIR technique to deal with the temperature-dependent emission intensities of non-TCLs of luminescent compounds. To date, some compounds, such as BaTiO 3 :Er 3+ /Ho 3+ /Yb 3+ , La 3 Li 3 W 2 O 12 :Eu 3+ /Mn 4+ , Na 5 Y 9 F 32 :Ce 3+ /Tb 3+ , YVO 4 :Eu 3+ /Nd 3+ , LaGaO 3 :Cr 3+ /Nd 3+ , and Ca 14 Al 10 Zn 6 O 35 :Ti 4+ /Eu 3+ , − with good thermometric properties, in which the non-TCLs are used, have been developed to realize contactless temperature sensing. Thereby, the utilization of the temperature-dependent FIR value of non-TCLs is a facile strategy to manipulate the thermometric behaviors of luminescent materials.…”