Relative Thermal Sensitivity Research Articles

Luminescent thermometry based on Er3+/Yb3+ co-doped yttrium niobate with high NIR emission and NIR-to-visible upconversion quantum yields

The growing demand aiming non-invasive diagnosis techniques applications has become an emerging field for developing more efficient bioprobes working in the near infrared (NIR) biological windows. In this work, we propose Er3+/Yb3+ co-doped yttrium niobate as a multifunctional material synthesized via sol-gel method. We study its NIR emission under UV excitation (down-shifting) and NIR-to-visible upconversion (UC) emission and exploit this material as a luminescent thermometer. X-ray diffraction analysis points out the formation of cubic Y3NbO7 crystalline phase after annealing at 1100 °C. Intense and narrow 1.5 μm emission (FWHM ∼24 nm) with Er3+4I13/2 lifetime value of ca. 5.5 ms are observed under excitation in the host absorption band (276 nm), due to down-shifting process. Down-shifting and upconversion quantum yields (QY) with excitation at 980 nm were reported for the first time for Y3NbO7 material with values of ca. 18% and ca. 0.0020% in the NIR and visible ranges, respectively. Y3NbO7 is a luminescent primary thermometer with maximum relative thermal sensitivity of 1.31 ± 0.06% K−1, temperature uncertainty of 0.31 K, and repeatability of 99.6%. Furthermore, the relatively high QY values in NIR and UC emission, comparable to fluorides and higher than other oxides, make Er3+/Yb3+ co-doped yttrium niobate an interesting multifunctional probe aiming for biological applications.

Highly-efficient double perovskite Mn4+-activated Gd2ZnTiO6 phosphors: A bifunctional optical sensing platform for luminescence thermometry and manometry

Remote temperature and pressure monitoring provides new and exciting chances to explore the variation of luminescence properties of compounds under extreme conditions. Herein, series of Mn4+-activated, double perovskite Gd2ZnTiO6 phosphors were prepared to develop novel, bifunctional sensors of temperature and pressure. Upon 345 nm excitation, bright red emission originating from Mn4+ is generated, and its intensity is affected by doping content, where the optimal intensity is achieved at 0.3 mol% of Mn4+ doping. The determined concentration quenching mechanism is mainly governed by a dipole–dipole interaction. The internal and external quantum efficiencies of the synthesized phosphors are as high as 95.6% and 83.2%, respectively. Besides, the crystal-field strength and nephelauxetic effect are theoretically discussed to identify their impacts on the emission characteristics of Mn4+. Furthermore, via analysing the temperature-dependent emission bandwidth and lifetime, the thermometric properties of the resultant phosphors are explored, and the maximum relative thermal sensitivities for the Gd2ZnTiO6:Mn4+ phosphor with optimal doping are 0.34% and 2.43% K−1 at 423 K, respectively. Additionally, the influence of pressure on the luminescence performance of the studied phosphors is investigated. When pressure increases, a significant red-shift of the emission band is observed, showing the pressure sensitivity is as high as 1.11 nm/GPa. Notably, during the compression and decompression processes, the prepared phosphors possess stable phase structure, which is confirmed by the pressure-dependent Raman spectra. These results suggest that the highly-efficient double perovskite Mn4+-activated Gd2ZnTiO6 phosphors are promising bifunctional luminescent platforms, for both luminescence thermometry and manometry applications.

Improved up-conversion behaviors and temperature sensitivity based on Stark sublevels of Er3+ in β-NaYF4:Yb3+, Er3+ and β-NaYF4:Yb3+, Er3+@NaGdF4

Rare earth ions doped core-shell thermometers exhibit improved up-conversion emission behaviors, while the thermal sensitivity is not higher than the corresponding core-only structured luminescent thermometers via the thermal coupled levels based luminescence intensity ratio (LIR) technique. In this work, the core-only β-NaYF4: 16Yb3+, 4Er3+ (C–4Er) up-conversion nanoparticles (UCNPs) and the sub 25 nm core-shell β-NaYF4: 16Yb3+, 4Er3+@0.5NaGdF4 (CS–4Er@0.5Gd) and β-NaYF4: 16Yb3+, 4Er3+@1NaGdF4 (CS–4Er@1Gd) UCNPs have been successfully synthesized by seed-mediated growth methods for temperature detection. The spectral study indicated that the up-conversion luminescence intensity of CS-4Er@0.5Gd and CS-4Er@1Gd was obviously enhanced compared withC-4Er. Luminescence intensity ratio originated from thermally coupled Stark sublevels (Stark-LIR) of Er3+ (2H11/2(1)(2), 4S3/2(1)(2)(3)) of CS-4Er@0.5Gd and CS-4Er@1Gd has been firstly applied to calculated the relative thermal sensitivity (SR) of core-shell UCNPs. As a result, SR of CS-4Er@1Gd is the largest among the considered UCNPs, and is increased from 10.95 × 10−3/K (LIR) to 17.80 × 10−3/K (Stark-LIR), indicating that with Stark-LIR techniques, the nano core-shell sensors behave a larger SR than core-only structured thermometers. This work may lead to an appropriate approach to improve the temperature sensitivity of core-shell thermometers for temperature sensing.

Luminescence nanothermometry via white light emission in Ho3+, Tm3+:Y2O3 colloidal nanocrystals

Cubic Ho3+ and Tm3+ doped Y2O3 colloidal nanotriangles with lateral length sizes ∼43 nm, were synthesized via thermal decomposition methodology. These colloidal nanocrystals, upon high power excitation at 808 nm, generate white light. The crystalline structure, size and shape, and the surface of the colloidal nanocrystals, were investigated before and after being exposed to laser excitation. Factors that might affect the generation of white light, such as the power of excitation source, the stability of the emission with time, and the temperature at which the colloidal nanocrystals were exposed, are analyzed. The white light displayed temperature-dependence optical properties, allowing the application of these nanocrystals as luminescent nanothermometers over a wide range of temperatures, from room temperature to 473 K. The relative thermal sensitivity and the temperature resolution of these luminescent nanothermometers are 3.38% K−1 and 0.15 K, respectively, at 473 K, enabling to demonstrate a new highly sensitive mechanism for luminescence thermometry.

Near-infrared absorption thermometry exploiting an anomalously large spectral line-shift for the Yb3+ cubic centre in CaF2:Yb3+/Er3+ nanoparticles

Near-infrared absorption spectra of Yb3+ in Er3+ co-doped CaF2 upconverting nanoparticles have been measured. The Yb3+ ion 2F7/2→2F5/2 inter-multiplet optical absorption spectra show negatively charged preferential clusters and non-locally charge compensated cubic centers as the dominant centres. The temperature dependent absorption spectra measured between 10 K and 413 K for Yb3+ cubic centres exhibit an anomalously large blue-shift of 16.90 ± 0.02 cm−1. The CaF2:Yb3+/Er3+ nanoparticles show an absolute thermal sensitivity Sa of 0.044 ± 0.001 cm−1⋅K−1 and the maximum relative thermal sensitivity Sr of 2.290 ± 0.010%·K−1 at 413 K region based on the large cubic centre absorption line-shift and a value of Sr of 0.0723 ± 0.001%·K−1 at 10 K (0.0562 ± 0.010%·K−1 at 413 K) from the line-width. The observed absolute absorption thermal sensitivity is 10 times higher (and the relative absorption thermal sensitivity is 2 times higher) than that obtained using the fluorescence intensity ratio of the thermally coupled 2H11/2,4S3/2 energy levels of Er3+ in co-doped nanoparticles.

Optical temperature sensing by tuning photoluminescence in a wide (visible to near infrared) wavelength range in a Eu3+-doped Bi-based relaxor ferroelectric.

The prevalent material design principles for optical thermometry primarily rely on thermally driven changes in the relative intensities of the thermally coupled levels (TCLs) of rare-earth-doped phosphor materials, where the maximum achievable sensitivity is limited by the energy gap between the TCLs. In this work, a new, to the best of our knowledge, approach to thermometric material design is proposed, which is based on temperature tuning of PL emission from the visible to the NIR region. We demonstrate a model ferroelectric phosphor, Eu3+-doped 0.94(Na1/2Bi1/2TiO3)-0.06(BaTiO3) (NBT-6BT), which, by virtue of the contrasting effects of temperature on PL signals from the host and Eu3+ intraband transitions, can achieve a relative thermal sensitivity as high as 3.05% K-1. This model system provides a promising alternative route for developing self-referencing optical thermometers with high thermal sensitivity and good signal discriminability.

Upconverting NIR-to-NIR LuVO4:Nd3+/Yb3+ Nanophosphors for High-Sensitivity Optical Thermometry.

Accurate contactless thermometry is required in many rapidly developing modern applications such as biomedicine, micro- and nanoelectronics, and integrated optics. Ratiometric luminescence thermal sensing attracts a lot of attention due to its robustness toward systematic errors. Herein, a phonon-assisted upconversion in LuVO4:Nd3+/Yb3+ nanophosphors was successfully applied for temperature measurements within the 323-873 K range via the luminescence intensity ratio technique. Dual-activating samples were obtained by codoping and mixing single-doped nanopowders. The effect of the type of dispersion system and the Yb3+ doping concentration was studied in terms of thermometric performances. The relative thermal sensitivity reached a value of 2.6% K-1, while the best temperature resolution was 0.2 K. The presented findings show the way to enhance the thermometric characteristics of contactless optical sensors.

White light source and optical thermometry based on zinc-tellurite glass tri-doped with Tm3+/Er3+/Sm3+

The potential of Tm3+/Er3+/Sm3+ tri-doped TeO2-Li2O-ZnO (TLZ) glasses for temperature sensors using color emissions and for generating white light sources was investigated. The samples were successfully synthesized by melting quenching technique in air atmosphere. We have used fixed concentrations of Tm3+ (0.2 mol%) and Er3+ (0.5 mol%) ions, and three Sm3+ concentrations: 0.2, 0.5, and 1.0 mol%. Particularly, we have analyzed the fluorescence intensity ratio (FIR) corresponding to the emissions of these ions as a function of the temperature. As a result, the highest value obtained to the relative thermal sensitivity was 2.47%K−1 for the FIR related to the emissions at 530 nm and 458 nm of the sample doped with 0.5 mol% of Sm3+. In addition, white-light emission was achieved by adjusting the doping concentration of Sm3+ ions. Moreover, we obtained a CIE color coordinates changing from white, (0.308, 0.317) at 299 K, to yellow, (0.416, 0.514) at 455 K. These results showed that these TLZ glasses are promising platforms for optical temperature sensing, for example, such as safety signal in high-temperature environment.

Mixing phosphors to improve the temperature measuring quality

Using luminescent materials for temperature measuring is considered the perspective remote technique nowadays. Designing new materials which combine a wide operating range with satisfying relative thermal sensitivity ( S r ) and temperature uncertainty values is still a challenge. In this paper, we study the luminescence properties and thermometric performance of a mixture of two phosphors. These are Ga-modified garnets - Y 3 (Al 3 Ga 2 )O 12 :0.1%Pr and Y 3 (Al 1 Ga 4 )O 12 :0.1%Pr - already reported as dual-mode luminescent thermometers. We show a new concept to improve important thermometric parameters of luminescence thermometers. We prove that such a mixture offers a significantly flatter course of the relative thermal sensitivity vs. temperature with S r around 1%K −1 over a broad temperature interval. Independently of which of the thermometric parameter is used, temperature measurement may be easily executed in the broad range of temperatures, 15–675 K. At the core of our concept is the use of two phosphors of the same crystal structure. This allows for the equally effective excitation of the two components of the mixture, while both use the same activator. • Dual-mode thermometry is executed over 15–675 K range mixing two phosphors. • The Mixed phosphors belong to the same crystal structure of Pr activated garnets. • The same crystal structure allowed efficient excitation with the same energy. • The Mixed phosphors allowed to improve the accuracy of temperature measuring.

One ion to catch them all: Targeted high-precision Boltzmann thermometry over a wide temperature range with Gd3+

Ratiometric luminescence thermometry with trivalent lanthanide ions and their 4fn energy levels is an emerging technique for non-invasive remote temperature sensing with high spatial and temporal resolution. Conventional ratiometric luminescence thermometry often relies on thermal coupling between two closely lying energy levels governed by Boltzmann’s law. Despite its simplicity, Boltzmann thermometry with two excited levels allows precise temperature sensing, but only within a limited temperature range. While low temperatures slow down the nonradiative transitions required to generate a measurable population in the higher excitation level, temperatures that are too high favour equalized populations of the two excited levels, at the expense of low relative thermal sensitivity. In this work, we extend the concept of Boltzmann thermometry to more than two excited levels and provide quantitative guidelines that link the choice of energy gaps between multiple excited states to the performance in different temperature windows. By this approach, it is possible to retain the high relative sensitivity and precision of the temperature measurement over a wide temperature range within the same system. We demonstrate this concept using YAl3(BO3)4 (YAB):Pr3+, Gd3+ with an excited 6PJ crystal field and spin-orbit split levels of Gd3+ in the UV range to avoid a thermal black body background even at the highest temperatures. This phosphor is easily excitable with inexpensive and powerful blue LEDs at 450 nm. Zero-background luminescence thermometry is realized by using blue-to-UV energy transfer upconversion with the Pr3+−Gd3+ couple upon excitation in the visible range. This method allows us to cover a temperature window between 30 and 800 K.

Optical thermometry through infrared excited green upconversion emissions of Er3+ -Yb3+ co-doped LaAlO3 phosphors

Er3+/Yb3+ single- and co-doped LaAlO3 ceramic phosphors have been synthesized by the conventional solid-state reaction method. The structural, morphological, and optical properties of (z at. %) Er: LaAlO3, (1 at.% Er), (y at.% Yb): LaAlO3, and (7 at.% Yb), (x at.% Er): LaAlO3 samples were investigated. The upconversion (UC) luminescence spectra of (Er3+, Yb3+): LaAlO3 phosphors exhibit strong green and weak red emissions under 973 nm excitation. By measuring the power dependence of the UC emission intensity, it was shown that the 4S3/2, 2H11/2, and 4F9/2 levels responsible for the green and red emissions, respectively, are populated by two-photon processes. The luminescence decay of the 4S3/2 (Er3+) level was analyzed. The luminescence intensity ratio (LIR) temperature dependence for the thermally coupled levels (2H11/2 and 4S3/2) of Er3+ ions in (1 at. % Er, 7 at. % Yb): LaAlO3 sample was calculated and the variations of absolute thermal sensitivity (Sa) and relative thermal sensitivity (Sr) with temperature were determined. The maximum values obtained for the Sr and Sa parameters were Sr = 2.44% K−1 at 175 K and Sa = 0.0048 K−1 at 400 K. The results show that (Er3+, Yb3+): LaAlO3 ceramic phosphors are suitable upconverting materials for green display devices and present great potential as non-contact optical temperature sensors.

Going Above and Beyond: A Tenfold Gain in the Performance of Luminescence Thermometers Joining Multiparametric Sensing and Multiple Regression (Laser Photonics Rev. 15(11)/2021)

Luminescence Nanothermometry Selecting green fluorescent protein and Ag2S nanocrystals as illustrative multiparametric thermographic phosphors, in article number 2100301, Luís D. Carlos and co-workers demonstrate that the synergy between multiparametric readouts and multiple linear regression makes possible a 10-fold improvement in the performance of luminescent thermometers reaching a world record in the relative thermal sensitivity (Sr = 50 %·K−1) and an impressive temperature uncertainty of 0.05 K.

1D-Zigzag Eu3+/Tb3+ Coordination Chains as Luminescent Ratiometric Thermometers Endowed with Multicolor Emission.

Two homometallic Coordination Polymers (CPs) with composition [Ln(hfac)3bipy]n (Ln3+ = Eu3+, 1, and Tb3+, 2; hfac = hexafluoroacetylacetonato, bipy = 4,4′-bipyridine) were used to develop a family of ratiometric luminescent thermometers containing Eu3+ and Tb3+ as red and green emitters, respectively. The thermometric properties of pure CPs and of their mixtures having an Eu3+/Tb3+ molar ratio of 1:1, 1:3, 1:5, and 1:10 (samples: Eu1Tb1, Eu1Tb3, Eu1Tb5, and Eu1Tb10) were studied in the 83–383 K temperature range. Irrespective of the chemical composition, we observed similar thermometric responses characterized by broad applicative temperature ranges (from 100 to 165 K wide), and high relative thermal sensitivity values (Sr), up to 2.40% K−1, in the physiological temperature range (298–318 K). All samples showed emissions endowed with peculiar and continuous color variation from green (83 K) to red (383 K) that can be exploited to develop a colorimetric temperature indicator. At fixed temperature, the color of the emitted light can be tuned by varying composition and excitation wavelength.

Mixed-valent MgAl2O4:Eu2+/Eu3+ phosphor for ratiometric optical thermometry

Novel strategies to obtain remote temperature sensing with good spatial and thermal resolution are in high demand in various applications, where traditional thermometers are inappropriate. The majority of developed luminescence thermometers utilize thermally-coupled levels with their inherent limitation of thermal sensitivity and problems with signal discriminability. We report mixed-valent Eu2+/Eu3+-doped MgAl2O4 phosphor as a ratiometric thermal sensor, which is free of these drawbacks. Different temperature behavior of Eu2+ and Eu3+ emission bands provides luminescence thermometry within range of 298–523 K. High absolute and relative thermal sensitivities of 0.084 K-1 and 0.83% K−1, respectively, as well as sub-degree temperature resolution indicate that MgAl2O4:Eu2+/Eu3+ phosphor is a promising material for optical thermometry.

Dual-center thermochromic Bi2MoO6:Yb3+, Er3+, Tm3+ phosphors for ultrasensitive luminescence thermometry

Optical thermometers are of great interest due to their non-contact, high-sensitivity and fast measurement characteristics. In this work, a series of dual-center Bi1.96−xMoO6: 0.02Er3+, 0.02Tm3+, xYb3+ (x = 0.10–0.35) upconverting materials were prepared by a sol-gel synthesis method. Upon 975 nm excitation, the prepared materials exhibit bright color-tunable (from yellow to orange) upconversion (UC) emissions, as the Yb3+ content increases. The thermometric properties of the synthesized materials associated with different thermally-coupled and non-thermally coupled levels of Tm3+ and Er3+ were systematically investigated. Based on the temperature-dependent emissions originating from the non-thermally coupled levels of Tm3+ (3F2,3) and Er3+ (4F9/2), i.e., their band intensity ratios 700/670 nm, the developed optical thermometers were found to exhibit an exceptional relative thermal sensitivity (Sr), up to 5.90% K−1 at 293 K. Importantly, in the whole T-range of 293–623 K, the Sr values are larger than 2% K−1. Furthermore, it is revealed that the position of the Tm3+ emission band, centered around 800 nm is highly dependent on temperature, and, so, it can be utilized as a second thermometric parameter, which is important for a multi-parameter temperature sensing in the T-range of 293–623 K. These results suggest that Er3+/Tm3+/Yb3+-doped Bi2MoO6 materials are promising candidates for ultra-sensitive, dual mode optical thermometers and safety sign applications.

Going Above and Beyond: A Tenfold Gain in the Performance of Luminescence Thermometers Joining Multiparametric Sensing and Multiple Regression

AbstractLuminescence thermometry has substantially progressed in the last decade, rapidly approaching the performance of concurrent technologies. Performance is usually assessed through the relative thermal sensitivity, Sr, and temperature uncertainty, δT. Until now, the state‐of‐the‐art values at ambient conditions do not exceed maximum Sr of 12.5% K−1 and minimum δT of 0.1 K. Although these numbers are satisfactory for most applications, they are insufficient for fields that require lower thermal uncertainties, such as biomedicine. This has motivated the development of materials with an improved thermal response, many of them responding to the temperature through distinct photophysical properties. This paper demonstrates how the performance of multiparametric luminescent thermometers can be further improved by simply applying new analysis routes. The synergy between multiparametric readouts and multiple linear regression makes possible a tenfold improvement in Sr and δT, reaching a world record of 50% K−1 and 0.05 K, respectively. This is achieved without requiring the development of new materials or upgrading the detection system as illustrated by using the green fluorescent protein and Ag2S nanoparticles. These results open a new era in biomedicine thanks to the development of new diagnosis tools based on the detection of super‐small temperature fluctuations in living specimens.

A Sensitive and Reliable Organic Fluorescent Nanothermometer for Noninvasive Temperature Sensing.

Sensing temperature at the subcellular level is of great importance for the understanding of miscellaneous biological processes. However, the development of sensitive and reliable organic fluorescent nanothermometers remains challenging. In this study, we report the fabrication of a novel organic fluorescent nanothermometer and study its application in temperature sensing. First of all, we synthesize a dual-responsive organic luminogen that can respond to the molecular state of aggregation and environmental polarity. Next, natural saturated fatty acids with sharp melting points as well as reversible and rapid phase transition are employed as the encapsulation matrix to correlate external heat information with the fluorescence properties of the luminogen. To apply the composite materials for biological application, we formulate them into colloidally dispersed nanoparticles by a technique that combines in situ surface polymerization and nanoprecipitation. As anticipated, the resultant zwitterionic nanothermometer exhibits sensitive, reversible, reliable, and multiparametric responses to temperature variation within a narrow range around the physiological temperature (i.e., 37 °C). Taking spectral position, fluorescence intensity, and fluorescence lifetime as the correlation parameters, the maximum relative thermal sensitivities are determined to be 2.15% °C-1, 17.06% °C-1, and 17.72% °C-1, respectively, which are much higher than most fluorescent nanothermometers. Furthermore, we achieve the multimodal temperature sensing of bacterial biofilms using these three complementary fluorescence parameters. Besides, we also fabricate a cationic form of the nanothermometer to facilitate efficient cellular uptake, holding great promise for studying thermal behaviors in biological systems.

1000 K optical ratiometric thermometer based on Er3+ luminescence in yttrium gallium garnet

The temperature dependence of the Er3+ green luminescence in Y3Ga5O12 crystal were analysed under ultraviolet and near-infrared laser excitations for optical sensing purposes. Changes in the relative green emission intensities from the 2H11/2 and 4S3/2 thermally-coupled multiplets to the 4I15/2 ground state were measured from room temperature up to 1000 K. The calibrated temperature scale shows a maximum in the absolute thermal sensitivity of ~23.9 × 10−4K−1 at 580 K and a relative thermal sensitivity of ~1.36%K−1 at RT, combining results for both blue and near-infrared laser excitations. The excellent results obtained, compared with other Er3+-based optical temperature sensors, are a consequence of the advantages of garnet crystals as optically efficient hosts that, apart from an impressive capability to be synthesized both as bulk and fiber forms, allow extending the long working temperature range up to 1000 K, and beyond, to the melting point limit close to 2000 K. In addition, the use of green emissions for the temperature calibration, with negligible black-body radiation disturbance, only needs a low-cost, basic setup that uses commercially available lenses, lasers and detectors. All these facts support the Er3+-doped Y3Ga5O12 garnet crystal as a potential candidate as temperature sensor, showing large sensitivity and good temperature resolution for ultra-high temperature industrial applications.

Multifunctional carbon dots derived from dansyl chloride for ratiometric thermal sensor and reactive oxygen generation

Carbon quantum dots (CDs) have emerged as a promising alternative of metal-free nanomaterials for a great variety of sensor applications. In this context, the present study is devoted to the characterization of morphological and spectroscopic properties of carbon dots derived from 5-(dimethylamino)naphthalene-1-sulfonyl chloride (dansyl chloride). By using the hydrothermal synthetic method, we obtain carbon dots (CD-DsCl) co-doped with nitrogen and sulfur, which exhibit a blue emission with a good quantum yield (16%) upon photoexcitation at 320 nm. The thermal and pH effects on CD-DsCl photoluminescence are also investigated, where a pronounced modification in the fluorescence spectrum takes place as the temperature and pH are varied. Our results indicate a relevant contribution of a thermally-activated mechanism to the CD-DsCl fluorescence. Furthermore, we analyze the possibility of using CD-DsCl in nanothermometry applications, determining the absolute and relative thermal sensitivities and thermal stability of nanoparticles in the temperature range of biological systems. In addition, it is also investigated the possibility of using CD-DsCl to generate reactive oxygen species (ROS) upon photoexcitation, envisaging their use as photosensitizers in photodynamic therapy applications. Within the above scenario, the present study shows that carbon dots derived from dansyl chloride possess interesting fluorescent properties, which can be exploited as a multifunctional material.

Exploring the Impact of Structure-Sensitivity Factors on Thermographic Properties of Dy3+-Doped Oxide Crystals.

Optical absorption spectra and luminescence spectra were recorded as a function of temperature between 295 K and 800 K for single crystal samples of Gd2SiO5:Dy3+, Lu2SiO5:Dy3+, LiNbO3:Dy3+, and Gd3Ga3Al2O12:Dy3+ fabricated by the Czochralski method and of YAl3(BO3)4:Dy3+ fabricated by the top-seeded high temperature solution method. A thermally induced change of fluorescence intensity ratio (FIR) between the 4I15/2→ 6H15/2 and 4F9/2 → 6H15/2 emission bands of Dy3+ was inferred from experimental data. It was found that relative thermal sensitivities SR at 350 K are higher for YAl3(BO3)4:Dy3+ and Lu2SiO5:Dy3+than those for the remaining systems studied. Based on detailed examination of the structural peculiarities of the crystals it was ascertained that the observed difference between thermosensitive features cannot be attributed directly to the dissimilarity of structural factors consisting of the geometry and symmetry of Dy3+ sites, the number of non-equivalent Dy3+ sites, and the host anisotropy. Instead, it was found that a meaningful correlation between relative thermal sensitivity SR and rates of radiative transitions of Dy3+ inferred from the Judd–Ofelt treatment exists. It was concluded that generalization based on the Judd–Ofelt parameters and luminescence branching ratio analysis may be useful during a preliminary assessment of thermosensitive properties of new phosphor materials.