High Thermal Sensitivity Research Articles

Constructing Nitrogen-Rich Fused [5,6,5]-Tricyclic Frameworks Through Rearrangement: Heat-Resistant Zwitterionic Salt Energetic Materials.

This study synthesized nitrogen-rich [5,6,5] fused compounds through a novel rearrangement reaction. Owing to its unique zwitterionic salt structure, rearrangement product 4-1 exhibits high thermal stability (Td > 250 °C), low sensitivity (IS > 40 J, FS > 360 N), and acceptable detonation velocities and pressures (νD = 8520 m s-1 and P = 32.53 GPa, respectively), which are better than those of TNT and TATB. These indicate the potential of zwitterionic salts as thermally stable energetic materials and provide new synthesis strategies for constructing fused polycyclic heterocycles through rearrangement.

Wide-range emission of Er3+/Yb3+ co-doped lanthanum niobates: A study of temperature and excitation-dependent luminescence aiming at applications in Biophotonics

We have synthesized Er3+,Yb3+ co-doped lanthanum niobate samples by a sol–gel route and investigated their luminescent properties under different excitation sources aiming at applications in Biophotonics. The samples were crystalline and composed primarily of orthorhombic La3NbO7 with secondary formation of monoclinic LaNbO4. We verified NIR-to-visible upconversion with the naked eye under excitation at 980 and 1550 nm; emission in the green and red regions prevailed, respectively. X-ray excitation revealed prevalent emission in the blue region, attributed to the luminescence of NbO43− groups in the lattice, as well as Er3+ emissions in the visible range. All the samples presented high relative thermal sensitivity (above 1.32 % K−1) and repeatability above 97 % between 243 and 293 K. Based on the investigated luminescent properties, the samples prepared herein are versatile materials with a wide range of potential applications as scintillators, optical markers, energy converters for photodynamic therapy, and nanothermometers.

Temperature Dependent Photoluminescence Properties of a Y2Ge2O7:Tb3+ phosphors. A dual band ratiometric luminescent thermometer

A series of green light emitting Y2Ge2O7:xTb3+ phosphors (x = 0.2, 0.5, 1.0, 2.0 and 4.0mol%) were obtained via the solid-state reaction method. The single phase was confirmed by XRD technique. The photoluminescence (PL) excitation spectrum, emission spectra at room and as a function of temperature, decay curves of phosphors were studied in detail. The emission spectra show typical emissions of Tb3+ ions, whose relative intensities change with the ion concentration or UV excitation. A shift of the CIE chromaticity coordinates from blueish to green region was observed. The emission decay curves are compatible with a single type of Tb3+ activator. The obtained internal Quantum Yield (iQY) increase with the terbium concentration, up to 10.0% for sample with 4.0mol%. In addition, the relative sensitivity values (Sr) for samples with 1.0 and 2.0mol% reached 0.97 and 2.02%K-1, respectively. These high thermal sensitivities obtained, in comparison with other Tb3+ based optical temperature sensors, in biophysical temperature range (30–45 °C), illustrates the potential use of Y2Ge2O7:xTb3+ phosphors in the design of efficient FIR luminescent thermometers for biological systems or other industrial applications.

Responsive integration performed by laser-induced Er3+ structural doping and graphene nanoplatelets

Laser-induced preparation method has the advantages of high efficiency, high yield, no ionic diffusion restriction and competitive side reaction, which can prepare diversified composite materials based on small-scale and distributed characteristics. Besides, integrating multiple performance and conducting inductive feedback are helpful for the reliability and calibration of laser-induced materials in the precision field. Herein, responsive integration is designed based on graphene nanoplatelets/ZnSe:Er3+ composite with optical, electrical, thermal and visual properties for real-time feedback. Er3+ ions doped ZnSe is obtained by fast laser-induced method, combined with two-dimensional graphene nanoplatelets and assembled into temperature-sensitive polyimide and cellulose paper, realizing the characteristics of photoelectric conversion and photothermal conversion. Besides, red fluorescence guiding perceptual behavior can also be produced under the radiation of NIR laser. Based on the proposed composite, bionic flower is constructed, and exhibits good motion features in blooming. Meanwhile, large curvature bending, high thermal sensitivity and strong fluorescence emission are also revealed. Such performance combination design provides a convenient approach for multi signals cross feedback in soft actuator, which strengthens the monitoring and guidance of motion perceptions, and can be potentially applied in diversified fields.

Multimodal Temperature Readout Boosts the Performance of CuInS2/ZnS Quantum Dot Nanothermometers.

Fluorescent nanothermometers are positioned to revolutionize research into cell functions and provide strategies for early diagnostics. Fluorescent nanostructures hold particular promise to fulfill this potential if nontoxic, stable varieties allowing for precise temperature measurement with high thermal sensitivities can be fabricated. In this work, we investigate the performance of micelle-encapsulated CuInS2/ZnS core/shell colloidal quantum dots (QDs) as fluorescent nanothermometers. We demonstrate four temperature readout modes, which are based on variations in the photoluminescence intensity, energy, and lifetime and on a specific ratio of excitation efficiencies. We further leverage this multimodal readout to construct a fifth, multiparametric thermometer calibration based on the multiple linear regression (MLR) model. We show that the MLR approach boosts the thermometer sensitivity by up to 7-fold while reducing the readout error by about a factor of 3. As a result, our QDs offer the highest sensitivities among semiconducting QDs emitting in the first biological window. The obtained results indicate that CuInS2/ZnS QDs are excellent candidates for intracellular in vivo thermometry and provide guidelines for further optimization of their performance.

Lanthanide-Doped Nanoparticles Anchoring on Metal-Organic Frameworks with Thermally Enhanced Upconversion Luminescence for Sensitive Nanothermometers.

Nanothermometers can detect changes in the local temperature in living cells and in vivo, revealing fundamental biological properties. Despite the exploration of different temperature-responsive materials, the design and development of temperature-sensing probes with high brightness and high sensitivity remain a daunting challenge. Here, we employed the UiO-66 type metal-organic frameworks (MOFs) to anchor UNCPs on the surface of the MOFs for constructing MOF@UCNPs nanohybrids. The in situ composite method with MOFs leads to the coordination interaction between the ligands and the surface of UCNPs, enabling controlled composite formation between different MOFs and UCNPs. Remarkably, the surface interaction favors the anomalous thermo-enhanced luminescence, achieving a 35-fold enhancement of UiO-66@NaYF4:Yb/Tm at 413 K. Furthermore, these MOF@UCNPs nanohybrids with thermo-enhanced luminescence are developed as multifunctional biological probes for bioimaging and intracellular temperature sensing, demonstrating a high thermal sensitivity of 1.92% K-1 in the physiological temperature range. Based on these findings, temperature monitoring of the local position was successfully carried out by the designed MOF@UCNPs nanoprobes in vivo. These findings underscore the potential of MOF@UCNPs nanohybrids, opening up new avenues for the development of a multifunctional platform for biological analysis.

High thermal sensitivity and dielectric constants in CaCu3Ti4O12-LaMn1-Fe O3 composite ceramics by designing sandwich and core-shell structure

High thermal sensitivity and dielectric constants in CaCu3Ti4O12-LaMn1-Fe O3 composite ceramics by designing sandwich and core-shell structure

High sensitivity metamaterial thin film: bio and thermal sensors based on Fano resonances and nematic liquid crystals

ABSTRACT In this research, a new sensor was designed that exhibits high biological and thermal sensitivities. It is suitable for use as a biosensor, a thermal sensor, or both simultaneously. This nanostructure sensor is based on two non-identical copper rings, which are dependent on two dielectric environments, and has been optimised to enhance sensitivity. To control and increase the sensitivity of the designed metamaterial, the E7 liquid crystal was used, which has a temperature-dependent refractive index. The optimised data indicate that the highest sensitivity for the structural parameters; R, dr and d are 70, 43 and 30 nm, respectively. This nanostructure demonstrates a refractive index sensitivity of 500 nm/RIU and a very high temperature sensitivity of 11 nm/K in the wavelength range of 500–1000 nanometres and a temperature range of 290–330 Kelvin. The second peak has the highest sensitivity to the refractive index and the third peak has the highest sensitivity to temperature. The high temperature sensitivity reported is at a 90-degree orientation angle of the liquid crystal director. Therefore, the simulation and optimisation of this ultra-thin film indicates that it can be suitable for use as a high-quality bio-thermal sensor with a high figure of merit.

A new red phosphor for high time-resolved thermal sensitivity and plant growth.

Luminous materials with a rapid lifetime response have garnered significant interest in sensing technology. In this work, the transition element Mn doped phosphor Sr2TiO4:Mn4+ was synthesized by a traditional high temperature solid phase method. The emission peak of Sr2TiO4:0.009Mn4+ aligns closely with the absorption peak of phytochrome Pfr. The temperature-dependent photoluminescence (PL) spectra and lifetime of Sr2TiO4:0.009Mn4+ were examined within the temperature range of 273-323 K. The temperature sensing characteristics based on the lifetime were analyzed, and the maximum relative sensitivity was 14.93% K-1 at 309 K. The high sensitivity of the Sr2TiO4:0.009Mn4+ phosphor makes it a promising material for temperature sensing applications.

Boltzmann thermometry: Eu3+-doped monoclinic Y2O3 and Y2O3@SiO2 nanoparticles

During last decade optical thermometry has gained considerable attention due to the possibility to determine temperature remotely in cases when traditional contact methods fail. The most widespread type of optical temperature sensors is based on monitoring luminescence intensity ratio between transition originated from thermally coupled energy levels. Eu3+ ions own the largest energy gap between thermally coupled 5D1 and 5D0 energy levels among all lanthanides, which guarantees a high thermal sensitivity of Boltzmann-type thermometry. Here, uncoated m-Y2O3:Eu3+ and core-shell m-Y2O3:Eu3+@SiO2 nanophosphors have been successfully utilized as ratiometric thermal sensors within the 298–873 K range. It was shown that the calculation method (integral or peak intensities) only slightly affects thermal sensitivity. SiO2 coating significantly enhances emission intensity and increases lifetime, but has no noticeable effect on thermal sensitivity. m-Y2O3:Eu3+ nanophosphor has the best thermometric characteristics of Sr = 0.96 % K-1 at 373K and δT = 0.5 K.

Environment-tolerant gelatin based ionic conductive organohydrogel for flexible sensor

Flexible wearable devices based on hydrogels have attracted more and more attention, however, the preparation of hydrogels with high toughness, conductivity and anti-freezing and anti-drying is still a challenge. In this study, a chemical-physical cross-linked double network conductive organohydrogel was designed by incorporating gelatin and Lithium chloride (LiCl) into polyacrylamide (AM) network with water-glycerol binary solvent. The results displayed that the organohydrogel exhibited high toughness, high stretchability, anti-freezing and anti-drying capability. With the addition of glycerol and LiCl, the organohydrogel has shown good conductivity in wide ranges of temperature. Moreover, the organohydrogel could be used as a strain sensor for the detection of various human body motions. Meanwhile, it was found that the introduction of LiCl enhanced the strain sensing performance, the stability and working temperature range. The sensors exhibited a high thermal sensitivity (5.72 % /℃), broad temperature detection range (0–65℃). These outstanding advantages indicated that the organohydrogels have potential application as strain and temperature sensors.

Ultrasensitive Biomimetic Skin with Multimodal and Photoelectric Dual-Signal Sensing.

Mimicking biological skin enabling direct, intelligent interaction between users and devices, multimodal sensing with optical/electrical (OE) output signals is urgently required. Owing to this, this work aims to logically design a stretchable OE biomimetic skin (OE skin), which can sensitively sense complex external stimuli of pressure, strain, temperature, and localization. The OE skin consists of elastic thin polymer-stabilized cholesteric liquid crystal films, an ion-conductive hydrogel layer, and an elastic protective membrane formed with thin polydimethylsiloxane. The as-designed OE skin exhibits customizable structural color on demand, good thermochromism, and excellent mechanochromism, with the ability to extend the full visible spectrum, a good linearity of over 0.99, fast response speed of 93 ms, and wide temperature range of 119 °C. In addition, the conduction resistance variation of ion-conductive hydrogel exhibits excellent sensing capabilities under pressure, stretch, and temperature, endowing a good linearity of 0.99998 (stretching from 0 to 150%) and high thermal sensitivity of 0.86% per °C. Such an outstanding OE skin provides design concepts for the development of multifunctional biomimetic skin used in human-machine interaction and can find wide applications in intelligent wearable devices and human-machine interactions.

A novel energetic pyridine-2-carbohydrazide copper perchlorate complex: synthesis, cationic ligand structure and properties

The pyridine-2-carbohydrazide copper perchlorate complex was synthesized, and it possessed high thermal stabilitiy and moderate sensitivity which was sensitive to laser and could detonate RDX.

Multifunctional Conductive Double-Network Hydrogel Sensors for Multiscale Motion Detection and Temperature Monitoring.

As typical soft materials, hydrogels have demonstrated great potential for the fabrication of flexible sensors due to their highly compatible elastic modulus with human skin, prominent flexibility, and biocompatible three-dimensional network structure. However, the practical application of wearable hydrogel sensors is significantly constrained because of weak adhesion, limited stretchability, and poor self-healing properties of traditional hydrogels. Herein, a multifunctional sodium hyaluronate (SH)/borax (B)/gelatin (G) double-cross-linked conductive hydrogel (SBG) was designed and constructed through a simple one-pot blending strategy with SH and gelatin as the gel matrix and borax as the dynamic cross-linker. The obtained SBG hydrogels exhibited a moderate tensile strength of 25.3 kPa at a large elongation of 760%, high interfacial toughness (106.5 kJ m-3), strong adhesion (28 kPa to paper), and satisfactory conductivity (224.5 mS/m). In particular, the dynamic cross-linking between SH, gelatin, and borax via borate ester bonds and hydrogen bonds between SH and gelatin chain endowed the SBG hydrogels with good fatigue resistance (>300 cycles), rapid self-healing performance (HE (healing efficiency) ∼97.03%), and excellent repeatable adhesion. The flexible wearable sensor assembled with SBG hydrogels demonstrated desirable strain sensing performance with a competitive gauge factor and exceptional stability, which enabled it to detect and distinguish various multiscale human motions and physiological signals. Furthermore, the flexible sensor is capable of precisely perceiving temperature variation with a high thermal sensitivity (1.685% °C-1). As a result, the wearable sensor displayed dual sensory performance for temperature and strain deformation. It is envisioned that the integration of strain sensors and thermal sensors provide a novel and convenient strategy for the next generation of multisensory wearable electronics and lay a solid foundation for their application in electronic skin and soft actuators.

ROS-mediated antifungal activity of Ocimum essential oil-loaded nanoemulsions against postharvest fungal pathogens of Kinnow

Kinnow fruit is prone to fungal and microbial attacks, leading to significant postharvest losses during marketing and storage due to two most prominent fungal pathogens, Penicillium digitatum and P. italicum. Safer alternatives of synthetic fungicides are required for management of these pathogens. Essential oils (EO) with remarkable antimicrobial activities may offer an upcoming alternative, but the high volatility, thermal sensitivity, and hydrophobicity limit their commercial applications. In the current study, coarse and nanoemulsions (CEs and NEs) of the most potent Ocimum species were evaluated as novel coatings for Kinnow. In a screening in vitro study, the efficacy of Ocimum essential oil of three species against P. digitatum and P. italicum was assessed. The CEs and NEs (0.5%–0.3% concentrations) of Ocimum viride EO (OVEO, best screened EO) with three surfactants in 1:1 oil-surfactant proportion (OSP) were prepared. The NE formulated with 1% oil having OSP (1:1) sonicated for 10 min exhibited consistent stability till 1 month with mean droplet diameter of 180.2 nm, polydispersity index 0.328, ζ-potential (−22.58 mV) and pH of 7.84) exhibited complete inhibition of hyphal growth of test fungi at 500 mg L−1. The EO-NE treatment of the fungal hyphae led to enhanced generation of reactive oxygen species (ROS) manifested as hyphal distortion and suppression of spore germination as compared to EO. OVEO NEs may offer an ecofriendly alternate to synthetic analogues for postharvest management of Kinnow.

Production and characterization of plantaricin Y11 from <i>Lactiplantibacillus Plantarum</i> strain y11 (MW642245.1) isolated from Nigerian food samples and their applications in preserving milk

Bacteriocin from lactic acid bacterium (LAB) was characterized and its biopreservation assay carried out using conventional methods and integrative approaches. About 66.7% (n=180) of the bacterial strains isolated from twelve different fermented/non-fermented food products were potential LAB strains by biochemical characterization. The highest bacteriocin producing strain was selected and confirmed with 16S rRNA sequencing and submitted to GenBank of National Center for Biotechnology Information as Lactiplantibacillus plantarum strain Y11 (Accession number: MW642245.1). Polymerase Chain Reaction (PCR) revealed the presence of virulence genes (cytotoxin K and haemolysin C) in L. plantarum Y11. The bacteriocin produced was labelled as plantaricin Y11 with molecular weight of 1540 Da, amino acid sequence was NSHGTADYCVMWLIXK, and possessed the merits of wide pH stability (2–10), high thermal stability and sensitivity to protease. The bacteriocin showed wide spectrum of activity against bacterial reference strains with bacteriocin activity ranging from 3200Au/mL to 6400Au/mL. Preservative potentials of the bacteriocin compared favourably with sodium benzoate in milk, inhibiting bacterial and fungal load compared to the control. There was log reduction of aerobic mesophilic bacterial count of 8.02±0.15 and 8.43±0.21 Log 10 CFU/mL in milk treated with plantaricin Y11 and sodium benzoate, respectively. The log reductions of fungal count in plantaricin Y11 and sodium benzoate treated milk ≥4.41±0.11 and ≥3.1±0.2 Log 10 CFU/mL respectively. The plantaricin Y11 was then classified as class IIa in bacteriocin classification schemes and it sustained some organoleptic conditions of milk making it a promising candidate for safe bio-preservatives.

Achieving thermochromic upconversion of Tm3+ for high-sensitive nanoprobe and information encryption

Upconversion-based optical thermometry has many merits, such as quick temperature response, higher thermal sensitivity and robust reliability. However, the previous works were mainly focused on the thermally coupled emissions, limiting their thermal sensitivity due to the intrinsic constraint by small energy gaps (e.g., <2000 cm−1) according to Boltzmann distribution theory. Here, we report a design of NaYF4:Yb3+/Tm3+@NaYF4 core-shell nanostructure to achieve thermochromic upconversion and high thermal sensitivity by taking advantage of nonthermally coupled upconversion emissions of Tm3+. We show that the blue upconversion emission of Tm3+ at 475 nm (1G4→3H6) exhibits a regular decrease with elevating temperature, while its deep-red emission at 696 nm (3F2,3→3H6) presents an increase. Such a feature leads to a rapid rise of luminescence intensity ratio (I696 nm/I475 nm) and the optimal relative sensitivity (Sr) reaches 2.79 % K−1 (503 K). More interestingly, the sample gives rise to a gradual emission color change from blue to purplish-red with lifting temperature. Our results offer a new class of upconversion-based nonoprobe with high thermal sensitivity and observable emission color variation, showing a great potential for nanoprobe and information security.

Biocrusts modulate carbon losses under warming across global drylands: A bayesian meta-analysis

Biocrusts are critical biological components of drylands and play an important role in soil carbon (C) cycling. However, the effect of biocrusts on soil CO2 exchange across global gradients of temperature and moisture is poorly understood. Moreover, their response to climate change remains highly uncertain. Bayesian hierarchical meta-analyses were performed on 47 published studies to quantify the impact of biocrusts on net soil exchange (NSE) of carbon- the difference between respiration and photosynthesis. Meta-analyses were also used on 23 studies to examine the effects of experimental warming on NSE in biocrusts. Meta-regressions further explored the thermal and wetness sensitivities of biocrust NSE and potential adaptation of biocrust responses to climate change. The development of biocrusts in dryland soils significantly increased NSE by 66.5 [22.2, 112.2] g C m−2yr−1, despite seasonal fluctuations, indicating a net loss of carbon to the atmosphere. Experimental warming, on average, increased biocrust NSE by 22.9 [-0.1, 40.8] g C m−2yr−1 per °C. However, across the spatial climate gradient, aridity limited the effects of warming, while high temperature decreased the thermal sensitivity of biocrust NSE, thus supporting the thermal adaptation of biocrusts. These results emphasize the critical role of biocrusts in modulating soil carbon exchange in response to climate warming across drylands, with particularly high thermal sensitivity in cool and moist regions. This highlights the need to incorporate biocrusts into global carbon budgets and models for a comprehensive understanding of their impact on the carbon cycle.

Regulating Exciton De-Trapping of Te4+ -Doped Zero-Dimensional Scandium-Halide Perovskite for Fluorescence Thermometry with Record High Time-Resolved Thermal Sensitivity.

Fluorescence thermometry has been propelled to the forefront of scientific attention due to its high spatial resolution and remote non-invasive detection. However, recent generations of thermometers still suffer from limited thermal sensitivity (Sr ) below 10% change per Kelvin. Herein, this work presents an ideal temperature-responsive fluorescence material through Te4+ -doped 0D Cs2 ScCl5 ·H2 O, in which isolated polyhedrons endow highly localized electronic structures, and the strong electron-phonon coupling facilitates the formation of self-trapped excitons (STEs). With rising temperature, the dramatic asymmetric expansion of the soft lattice induces increased defects, strong exciton-phonon coupling, and low thermal activation energy, which evokes a rapid de-trapping process of STEs, enabling several orders of magnitude changes in the fluorescence lifetime over a narrow temperature range. After regulating the de-trapping process with different Te4+ doping, a record-high Sr (27.36% K-1 ) of fluorescence lifetime-based detection is achieved at 325 K. The robust stability against multiple heating/cooling cycles and long-term measurements enables a low temperature uncertainty of 0.067 K. Further, the developed thermometers are demonstrated for the remote local monitoring of operating temperature on internal electronic components. It is believed that this work constitutes a solid step towards building the next generation of ultrasensitive thermometers based on low-dimensional metal halides.

Synthesis and optimization of Nd3+doped hydroxyapatite as NIR-to-NIR nanothermometers

Neodymium (Nd)-doped nanomaterials show excellent biothermal sensing (TS) properties due to the thermally coupled near-infrared (NIR) emission. However, Nd-doping in biomaterials like hydroxyapatite (HA) may offer added biocompatibility, a major concern for TS materials. Here we report the optimisation of Nd-doped hydroxyapatite (HAP) nanophosphors as potential nanothermometers operating within the biological windows. Different doping concentrations were analysed where 5% Nd3+ doped HAP (HAP:5%Nd) showed the highest luminescence output, which improved 4-fold after the annealing. Thus, the effect of annealing was also analyzed on optical properties and thermal sensing. The ratiometric luminescence thermal sensing of HAP:5%Nd revealed the linear behaviour in the temperature range of 25– 60 °C with a high relative thermal sensitivity value of 0.37% K−1 at 298 K. Furthermore, the synthesized nanocrystals showed excellent biocompatibility in vitro. Overall, HAP:5%Nd showed properties for implementation in biomedical applications.