Thermometer Application Research Articles

Luminescence properties of KBaYSi2O7:Ce/Eu-Tb phosphors for multifunctional applications.

In this work, the multifunctional KBaYSi2O7:Ce/Eu-Tb (KBYS:Ce/Eu-Tb) phosphors were synthesized by using the conventional high-temperature solid-state reaction, and the luminescence properties were investigated for LED and optical thermometer applications. The single-phase samples were checked by x-ray diffractometer patterns. The energy transfer was found in both Eu2+-Tb3+ and Ce3+-Tb3+ codoped samples, which was verified by spectra and decay curves. Correspondingly, the tunable emission was realized by adjusting the dopant concentrations and white light was obtained in the KBYS:4%Eu2+,9%Tb3+ sample, owing to the energy transfers among Eu2+, Tb3+, and Eu3+. By studying the temperature dependence of the KBYS:2%Ce3+,7%Tb3+, it has been found that the fluorescence intensity ratio for Tb3+ and Ce3+ emissions changes with temperature, indicating the potential application in an optical thermometer. The high absolute sensitivity was determined to be 0.012 K-1. By evaluating the thermal quenching luminescence of the KBYS:4%Eu2+,9%Tb3+, the thermal quenching temperature T0.5 was determined to be 555K, implying high thermally luminescent stability.

Reversible luminescence modulation and temperature‐sensing properties of Pr3+/Yb3+ codoped K0.5Na0.5NbO3 ceramics

AbstractIn this work, we have prepared a novel (K0.5Na0.5)0.99‐xPrxYb0.01NbO3 (abbreviated as KNN:xPr3+/0.01Yb3+, x = 0.0006, 0.0008, 0.001, 0.002, 0.003, and 0.004) ceramics, which possess visible UC emissions, photochromic (PC) and optical thermometric properties. Under the excitation of a 980‐nm diode laser, all the samples show the featured emissions of Pr3+ ions and the UC emission intensity is greatly dependent on the Pr3+ doping content. The optimal UC luminescence intensity is obtained at x = 0.001. All the prepared samples show a strong PC reaction, and a large luminescence quenching degree (ΔRt) of 74.94% is found. The optical thermometric properties of both the irradiated and unirradiated KNN:0.001Pr3+/0.01Yb3+ ceramics in the temperature range of 123‐573 K have been investigated via measuring the temperature‐dependent UC emission spectra of green emissions, which originate from the two 3P1 and 3P0 thermally coupled levels. It has been found that the prepared samples have both excellent PC behaviors and temperature‐sensing performances. These results suggest that the KNN:xPr3+/0.01Yb3+ ceramics are promising candidates for the applications in PC reaction and thermometers.

Inorganic Phosphors for Teaching a Holistic Approach to Functional Materials Investigation: From Synthesis and Characterization to Applications of Thermo- and Mechanoluminescence

Inorganic phosphors are the main component of light emitting diodes which have caused the revolution in lighting industry as an energy-efficient and long-lasting replacement of traditional incandescent light bulbs and fluorescent tubes. They are also used in various consumer products and displays and can potentially find applications in photocatalysis, solar cells, optical thermometers, and stress indicators. Long-afterglow phosphors provide an opportunity to visually observe and test different phenomena in solid-state materials and can be used as an effective teaching tool at the undergraduate level. We developed an upper-level undergraduate laboratory experiment that integrates the synthesis, processing, structural and spectroscopic characterization, and applications of strontium–aluminate-based phosphors. Observation of the intensity and duration of the phosphor afterglow under different conditions reinforces students’ learning of various concepts related to materials structure and properties, and spec...

Multi-site occupancies of Eu2+ in Ca6BaP4O17 and their potential optical thermometric applications

Single Eu2+ doped Ca6BaP4O17 materials are demonstrated to show potential optical thermometric applications with doping concentration-dependent luminescence and temperature-sensitive luminescence. Eu2+ ions occupy three types of lattice sites based on the results of Rietveld refinements, VUV–UV–vis (vacuum ultraviolet – ultraviolet – visible) luminescence spectra and time-resolved emission spectra. Due to site occupation and energy transfer, the emission color of Eu2+ doped Ca6BaP4O17 materials is tunable with the variation of the doping concentration of Eu2+. Then the energy transfer mechanism is analyzed using Inokuti-Hirayama, Yokota-Tanimoto, and Burshteĭn models, respectively. Because of the different thermal behaviors of Eu2+ luminescence in Ba2+, Ca2+(1) and Ca2+(2) sites, Ca6BaP4O17: Eu2+ phosphors appear obvious emission intensity evolutions with the increase of temperature, accompanying with the change of emission color under excitation at 300 and 400 nm, respectively. It indicates that Eu2+ doped Ca6BaP4O17 phosphors possess temperature sensitive luminescence characteristics. The temperature-dependent ratiometric emission intensity and the temperature recycle measurements verify the possibility of optical thermometric applications of Ca6BaP4O17: Eu2+ phosphors.

In situ temperature effect on spectral downshifting emission on Er3+ doped-Sr2CeO4 photoluminecent materials

In this work, the Er3+-doped Sr2CeO4 phosphors are reported, synthesized through a facile combustion method using citric acid as organic precursor, Ag+ as a cationic charge compensator and as a stabilizer of the photoluminescent phase of interest. FTIR, XRD and SEM results indicate the formation of the Sr2CeO4 with a high purity of phase obtained by this methodology. The spectral downshifting properties of the materials were investigated exciting the materials at UV-region. Emission spectra present a broad band emission positioned at 467 nm assigned to the cerate inorganic material phase and Er3+ emission bands at 525, 550 and 667 nm, attributed to the Er3+ transitions 2H11/2 → 4I15/2, 4S3/2 → 4I15/2 and 4F9/2 → 4I15/2, respectively. The excited state of the Sr2CeO4 and 4S3/2 phases of Er3+ was shown to be directly dependent on the Er3+ concentration. The observed behavior indicates a direct relation of the photoluminescence between the matrix and the Er3+.The mechanism of energy transfer is proposed and presented in this work. The influence of the in situ heating on the photoluminescence properties of the materials was also investigated. The results reveal that these down converter Er3+ materials have potential for thermometric applications.

Promising light converting BaMoO4:Er3+-Tm3+-Yb3+ phosphors for display and optical temperature sensing

Er3+-Tm3+-Yb3+ tri-doped BaMoO4 phosphors were synthesized by co-precipitation technique and characterized by X-ray diffraction analysis, absorption study and field emission scanning electron microscopy analysis. Upconversion as well as downconversion luminescence studies were performed by using near infrared (980 nm) and ultraviolet (380 nm) excitations. Energy level diagram, pump power dependence and colour coordinate study were utilized to describe the multicolor upconversion emission properties. Under single 980 nm diode laser excitation the dual mode sensing behaviour is realized via Stark sublevels and thermally coupled energy levels of the Tm3+ and Er3+ ions in the prepared tri-doped phosphors. A comparative fluorescence intensity ratio analysis for integrated emission intensities arising from the Stark sublevels {1G4(a) and 1G4(b)} and thermally coupled energy levels {2H11/2 and 4S3/2} of the Tm3+ and Er3+ ions, respectively was carried out in the prepared tri-doped BaMoO4 phosphors. The maximum sensitivity for thermally coupled energy levels of the Er3+ and Stark sublevels of the Tm3+ ion was reported. The developed phosphors could be useful in the display devices and optical thermometric applications.

Energy transfer from VO43− group to Sm3+ ions in Ba3(VO4)2:3xSm3+ microparticles: A bifunctional platform for simultaneous optical thermometer and safety sign

The Sm3+-doped Ba3(VO4)2 microparticles were successfully synthesized via a simple sol-gel method. Both the recorded three-dimensional photoluminescence (PL) emission spectra and counter lines revealed that the near-ultraviolet light was a proper excitation lighting source for the studied samples. Under 352 nm of irradiation, the effect of Sm3+ ion concentration on the PL emission properties of the microparticles was investigated and the optimum doping concentration was demonstrated to be 4 mol%. Based on the diversity in the thermal quenching performance of VO43− group and Sm3+ ions, a novel self-referencing non-invasion optical thermometer with high sensitivity and superior signal discriminability was designed. By taking the advantage of the temperature-dependent fluorescence intensity ratio between the VO43− group and Sm3+ ions, the optical thermometric properties of the Sm3+-doped Ba3(VO4)2 microparticles in the temperature range of 303–463 K were analyzed. The maximum absolute and relative sensor sensitivities, which were hardly influenced by the PL emission intensity, were obtained to be 0.039 K−1 and 2.24% K−1, respectively. Furthermore, the emitting color of the resultant compounds was found to be significantly dependent on the external temperature. These results suggest that the Sm3+-doped Ba3(VO4)2 microparticles are a potential candidate for high-performance self-referencing optical thermometer and safety sign applications.

Exploiting broader dynamic range in Si-bridge modified QTF’s for sensitive thermometric applications

The response of modified Quartz Tuning Forks (QTFs) on affixing an opto- or chemo-responsive bridging element between the terminal ends of the fork have been demonstrated to be both selective and highly sensitive. However, the Hookean model, widely employed in analysis currently, substantiates numerical accuracy when the stiffness of the bridging element is much smaller than that of the QTF motional arm. This paper presents a distributed beam model applicable for a broader range of stiffness ratios of the respective parts and is tested using a silicon bridging element to detect optically mediated thermal responses. Using this approach we demonstrate a sensor responsivity (ℜ) of 23 kN/m W, and a Noise Equivalent Power (NEP) of 8.5×10−7 W. The minimum detectable change in temperature of the bridge sensing element is calculated to be 2 mK. Thus, employing silicon bridging elements as demonstrated here, offers greater control over the reproducibility of the modified QTF over that of individually affixed polymer strands, as well as affords the opportunity to expand device reproducibility for larger scale implementation.

Fabrication of highly porous Y2O3:Ho,Yb ceramic and its thermometric applications

Highly porous Y2O3:Ho,Yb ceramic with relative high compressive strength was successfully fabricated by using NaF as pore-forming agent for the first time. The porosity, pore size, compressive strength and temperature-dependent upconversion luminescence of the as-fabricated porous Y2O3:Ho,Yb ceramic were investigated in detail. It was found that the open porosity and compressive strength of the as-fabricated porous Y2O3:Ho,Yb ceramic were 43.12% and 28.53 MPa, respectively, and the pore size was 4–8 μm. Under 980 nm excitation, the upconversion luminescence intensity ratio (I550/I665) of the 550 nm and 665 nm emissions varied from 8.10 to 4.63 with the temperature increasing from 293 K to 873 K. Porous Y2O3:Ho,Yb ceramic with such properties could be applied to ultra-high temperature ceramic structures for space application, luminescent probes and temperature sensors.

Preparation and dual sensing property of Zn2GeO4:Mn2+@ZIF-8 heterostructure chemosensor

Facile fabrication of new hybrids by post-modification approach is considered to be a straight forward strategy to develop new generation of chemosensor with high sensitivity and selectivity. In this work, a hybrid chemosensor prepared through surface modification of Zn2GeO4:Mn2+ nanorods by zeolitic imidazolate framework-8 (ZIF-8) is reported. Luminescent investigations revealed that the as-prepared Zn2GeO4:Mn2+@ZIF-8 heterostructure featured excellent sensing function with respect to temperature change from 298K to 423K, and Cu2+ ions concentration from 1×10−4mol·L−1 to 1×10−1mol·L−1. These results make Zn2GeO4:Mn2+@ZIF-8 composite superb candidate for luminescent applications in thermometers and metal ions detection.

Vanadium magnetite–melt oxybarometry of natural, silicic magmas: a comparison of various oxybarometers and thermometers

To test a recently developed oxybarometer for silicic magmas based on partitioning of vanadium between magnetite and silicate melt, a comprehensive oxybarometry and thermometry study on 22 natural rhyolites to dacites was conducted. Investigated samples were either vitrophyres or holocrystalline rocks in which part of the mineral and melt assemblage was preserved only as inclusions within phenocrysts. Utilized methods include vanadium magnetite–melt oxybarometry, Fe–Ti oxide thermometry and -oxybarometry, zircon saturation thermometry, and two-feldspar thermometry, with all analyses conducted by laser-ablation ICP–MS. Based on the number of analyses, the reproducibility of the results and the certainty of contemporaneity of the analyzed minerals and silicate melts the samples were grouped into three classes of reliability. In the most reliable (n = 5) and medium reliable (n = 10) samples, all fO2 values determined via vanadium magnetite–melt oxybarometry agree within 0.5 log units with the fO2 values determined via Fe–Ti oxide oxybarometry, except for two samples of the medium reliable group. In the least reliable samples (n = 7), most of which show evidence for magma mixing, calculated fO2 values agree within 0.75 log units. Comparison of three different thermometers reveals that temperatures obtained via zircon saturation thermometry agree within the limits of uncertainty with those obtained via two-feldspar thermometry in most cases, whereas temperatures obtained via Fe–Ti oxide thermometry commonly deviate by ≥50 °C due to large uncertainties associated with the Fe–Ti oxide model at T-fO2 conditions typical of most silicic magmas. Another outcome of this study is that magma mixing is a common but easily overlooked phenomenon in silicic volcanic rocks, which means that great care has to be taken in the application and interpretation of thermometers and oxybarometers.

ルビー及び、スピネル結晶の育成と光ファイバー温度計への応用 : バルク成長II

ルビー及び、スピネル結晶の育成と光ファイバー温度計への応用 : バルク成長II

Historical Review of Glasses Used for Parenteral Packaging.

Glass has long been used for packaging precious liquids, in particular pharmaceuticals. Its unique combination of hermeticity, transparency, strength, and chemical durability make it the optimal material for such an important role. Today's life-saving drugs are stored in borosilicate glasses, which evolved from applications in microscope optics and thermometers. As the glass compositions improved, so did the methods used to shape them and the tests used to characterize them. While all of these advances improved the quality of the glass container and its ability to protect the contents, problems still exist such as delamination, cracks, and glass particulates. In addition to these issues, we review new developments in glass composition development, performance, and testing in the 21st century.

Luminescent molecular thermometers for the ratiometric sensing of intracellular temperature

AbstractRecently, numerous luminescent molecular thermometers that exhibit temperature-dependent emission properties have been developed to measure the temperatures of tiny spaces. Intracellular temperature is the most interesting and exciting applications of luminescent molecular thermometers because this temperature is assumed to be correlated with all cell events, such as cell division, gene expression, enzyme reaction, metabolism, and pathogenesis. Among the various types of temperature-dependent emission parameters of luminescent molecular thermometers, the emission intensity ratio at two different wavelengths is suitable for accurate and accessible intracellular temperature measurements. In this review article, luminescent molecular thermometers that exhibit a temperature-dependent emission intensity ratio in living cells are summarized, and current progress in intracellular thermometry is outlined.

Site Occupancies, Luminescence, and Thermometric Properties of LiY9(SiO4)6O2:Ce3+ Phosphors.

In this work, we report the tunable emission properties of Ce3+ in an apatite-type LiY9(SiO4)6O2 compound via adjusting the doping concentration or temperature. The occupancies of Ce3+ ions at two different sites (Wyckoff 6h and 4f sites) in LiY9(SiO4)6O2 have been determined by Rietveld refinements. Two kinds of Ce3+ f-d transitions have been studied in detail and then assigned to certain sites. The effects of temperature and doping concentration on Ce3+ luminescence properties have been systematically investigated. It is found that the Ce3+ ions prefer occupying Wyckoff 6h sites and the energy transfer between Ce3+ at two sites becomes more efficient with an increase in doping concentration. In addition, the charge-transfer vibronic exciton (CTVE) induced by the existence of free oxygen ion plays an important role in the thermal quenching of Ce3+ at 6h sites. Because of the tunable emissions from cyan to blue with increasing temperature, the phosphors LiY9(SiO4)6O2:Ce3+ are endowed with possible thermometric applications.

Novel digital iteration algorithm for fluorescence lifetime measurement of multi-probe fiber thermometer

Abstract We report a novel digital iteration algorithm for fluorescence lifetime (FL) measurement, which is proved suitable for the fluorescence lifetime-based multi-probe fiber thermometer application. The algorithm utilizes only one set of fluorescence decay sampling data to decide the FL by using the basic addition and subtraction computation. Iteration number of about 10–12 times is sufficient to reach the final stable value. As a result, the algorithm features robust, high efficiency, strong anti-noise and immune to background level. The algorithm has been successfully used in a sapphire fiber-based multi-probe thermometer covering the temperature range from room temperature to 1000 °C and confirmed suitable for practical application.

Benefits of Silica Core-Shell Structures on the Temperature Sensing Properties of Er,Yb:GdVO4 Up-Conversion Nanoparticles.

We studied the temperature-dependent luminescence of GdVO4 nanoparticles co-doped with Er(3+) (1 mol %) and Yb(3+) (20 mol %) and determined their thermal sensing properties through the fluorescence intensity ratio (FIR) technique. We also analyzed how a silica coating, in a core-shell structure, affects the temperature sensing properties of this material. Spectra were recorded in the range of biological temperatures (298-343 K). The absolute sensitivity for temperature determination calculated for the core-shell nanoparticles is double the one calculated for bare nanoparticles, achieving a thermal resolution of 0.4 K. Moreover, silica-coated nanoparticles show good dispersibility in different solvents, such as water, DMSO, and methanol. Also, they show good luminescence stability without interactions with solvent molecules. Furthermore, we also observed that the silica coating shell prevents progressive heating of the nanoparticles during prolonged excitation periods with the 980 nm laser, preventing effects on their thermometric applications.

Fluorescent Molecular Rotor-in-Paraffin Waxes for Thermometry and Biometric Identification.

Novel thermoresponsive sensor systems consisting of a molecular rotor (MR) and paraffin wax (PW) were developed for various thermometric and biometric identification applications. Polydiphenylacetylenes (PDPAs) coupled with long alkyl chains were used as MRs, and PWs of hydrocarbons having 16-20 carbons were utilized as phase-change materials. The PDPAs were successfully dissolved in the molten PWs and did not act as an impurity that prevents phase transition of the PWs. These PDPA-in-PW hybrids had almost the same enthalpies and phase-transition temperatures as the corresponding pure PWs. The hybrids exhibited highly reversible fluorescence (FL) changes at the critical temperatures during phase transition of the PWs. These hybrids were impregnated into common filter paper in the molten state by absorption or were encapsulated into urea resin to enhance their mechanical integrity and cyclic stability during repeated use. The wax papers could be utilized in highly advanced applications including FL image writing/erasing, an array-type thermo-indicator, and fingerprint/palmprint identification. The present findings should facilitate the development of novel fluorescent sensor systems for biometric identification and are potentially applicable for biological and biomedical thermometry.

On the Fulfillment of Curie’s Law in Magnetic Fluids

A fulfillment of Curie’s law in magnetic fluids provides an option of their thermometric applications to measure thermodynamic temperature. On the other hand, it was shown elsewhere that the initial magnetic susceptibility χ of magnetic fluids follows Curie–Weiss’s law rather than Curie’s law. To obtain its values, use was made of the formula χ = М/Н0, where М is magnetization, and Н0 is the external magnetic field strength without any specimen. This work deals with investigations of the dependence of magnetic susceptibility of magnetic fluid on temperature for the cases where its values are found via the following formulas: 1) χ = М/Н0, and 2) χ = Мμ0/В, where В is the magnetic field induction inside the specimen. It is found that in the first case the temperature dependence of χ obeys Curie–Weiss’s law while in the second case – Curie’s law. The reason for this results from the fact that induction В acting on the particles of magnetic fluid is noticeably higher than that of the external field, В0.

Fiber-optic thermometer application of thermal radiation from rare-earth end-doped SiO₂ fiber.

Visible light thermal radiation from SiO2 glass doped with Y, La, Ce, Pr, Nd, Eu, Tb, Dy, Ho, Er, Tm, Yb, and Lu were studied for the fiber-optic thermometer application based on the temperature dependence of thermal radiation. Thermal radiations according to Planck's law of radiation are observed from the SiO2 fibers doped with Y, La, Ce, Pr, Eu, Tb, and Lu at the temperature above 1100 K. Thermal radiations due to f-f transitions of rare-earth ions are observed from the SiO2 fibers doped with Nd, Dy, Ho, Er, Tm, and Yb at the temperature above 900 K. Peak intensities of thermal radiations from rare-earth doped SiO2 fibers increase sensitively with temperature. Thermal activation energies of thermal radiations by f-f transitions seen in Nd, Dy, Ho, Er, Tm, and Yb doped SiO2 fibers are smaller than those from SiO2 fibers doped with Y, La, Ce, Pr, Eu, Tb, and Lu. Thermal radiation due to highly efficient f-f transitions in Nd, Dy, Ho, Er, Tm, and Yb ions emits more easily than usual thermal radiation process. Thermal radiations from rare-earth doped SiO2 are potentially applicable for the fiber-optic thermometry above 900 K.