High Temperature Sensor Research Articles

Transition-metal-doped biphenylene for enhanced CO detection: A high-throughput first-principles study

Our study examines the CO detection capabilities of pristine biphenylene (BP) and transition-metal-doped BP (M–BPx, x = 1 or 2), a novel two-dimensional nano-carbon material. Despite BP’s potential in toxic gas detection, its low CO adsorption energy (Eads) of 0.134 eV limits its application. Utilizing a combined strategy of high-throughput computational screening and DFT technique, we accurately identified the ground state configurations of CO-adsorbed M–BPx (M = Sc, Ti, Fe, Co, Ni, and Zn) and confirmed M doping significantly boosts BP’s CO adsorption ability, with Eads values ranging from 2.809 to 8.206 eV. This improvement is supported by ab initio molecular dynamics simulations and ionic d-p bonding interactions observed in electron localization functions, densities of state (DOS), and bond population analysis. Additionally, CO adsorption induces notable DOS changes in the M–BPx systems, validating the potential of M–BPx as suitable materials for CO detection. Notably, Zn-BP2 show notable work function shift after CO adsorption (0.36 eV), outperforming pristine BP’s 0.30 eV shift, and favorable recovery time (8.940 s). These shifts underscore the potential of Zn-BP2 for work function-based high-temperature CO sensor, marking it as a promising material for sensitive CO detection.

Direct Ink Writing of SiCN/RuO2/TiB2 Composite Ceramic Ink for High-Temperature Thin-Film Sensors.

Direct ink writing (DIW) of high-temperature thin-film sensors holds significant potential for monitoring extreme environments. However, existing high-temperature inks face a trade-off between cost and performance. This study proposes a SiCN/RuO2/TiB2 composite ceramic ink. The added TiB2, after annealing in a high-temperature atmospheric environment, forms B2O3 glass, which synergizes with the SiO2 glass phase formed from the SiCN precursor to effectively encapsulate RuO2 particles. This enhances the film's density and adhesion to the substrate, preventing RuO2 volatilization at high temperatures. Additionally, the high conductivity of TiB2 improves the film's overall conductivity. Test results indicate that the SiCN/RuO2/TiB2 film exhibits high linearity from room temperature to 900 °C, high stability (resistance drift rate of 0.1%/h at 800 °C), and high conductivity (4410 S/m). As a proof of concept, temperature sensors and a heat flux sensor were successfully fabricated on a metallic hemispherical surface. Performance tests in extreme environments using high-power lasers and flame guns verified that the conformal thin-film sensor can accurately measure spherical temperature and heat flux, with a heat flux sensor response time of 53 ms. In conclusion, the SiCN/RuO2/TiB2 composite ceramic ink developed in this study offers a high-performance and cost-effective solution for high-temperature conformal thin-film sensors in extreme environments.

Enhanced electrical properties and Vickers hardness of calcium bismuth niobate ceramics by W/Co substituted at B-site

Calcium bismuth niobate (CBN) ceramic, as a core element of high-temperature piezoelectric sensors, has attracted widespread attention due to its high Curie temperature within the class of Aurivillius compounds. However, CBN usually faces two shortcomings: poor piezoelectric constant and low resistivity. In this work, CBN-based ceramics with donor–acceptor ions (W/Co) co-substituted at B-site were prepared by solid-state reaction method, and structure–property relationship of ceramics was studied in detail. Co-substitution of W/Co ions effectively improved the electrical property and hardness of CBN ceramics. CaBi2Nb[Formula: see text](W[Formula: see text]Co[Formula: see text]O9 exhibits enhanced electrical and mechanical properties including high resistivity of [Formula: see text]cm at 500°C, piezoelectric constant of [Formula: see text] pC/N and hardness value of [Formula: see text][Formula: see text]GPa. These values are two orders of magnitude, over two times, and 1.36 times higher than those of pure CBN ceramic, respectively. This work provides a reference for exploring other bismuth-layered structural ceramics.

CSRR-SIW wireless passive high quality factor temperature sensor

CSRR-SIW wireless passive high quality factor temperature sensor

High Sensitivity Temperature Sensor Based on Directional Coupler in a Liquid-Filled Tapered Hollow Suspended Dual-Core Fiber

High Sensitivity Temperature Sensor Based on Directional Coupler in a Liquid-Filled Tapered Hollow Suspended Dual-Core Fiber

High sensitivity optical fiber temperature sensor based upon a polydimethylsiloxane filled Fabry-Perot interferometer

A high-sensitivity temperature sensor based upon an optical fiber Fabry-Perot interferometer (FPI) filled with polydimethylsiloxane (PDMS) is reported that employed a single mode fiber (SMF) and a hollow core fiber (HCF) to enhance the sensitivity. The sensing characteristics were investigated from 20 °C to 40 °C. The experimental results demonstrate that the sensor is sensitive to temperature due to the high thermal optical coefficient (TOC) and high thermal expansion coefficient (TEC) of PDMS, achieving a high sensitivity of 2.155 nm/°C. The designed sensor shows great potential for high-precision temperature sensing applications due to its high sensitivity, compact structure, and simple preparation.

High-temperature hydrogen sensor based on MOFs-derived Mn-doped In2O3 hollow nanotubes

Developing high-temperature hydrogen (H2) sensors with fast response speed is urgently demanded in harsh application environments, especially for chemical industries and the aerospace field. Herein, we have reported a facile strategy to synthesize Mn-doped In2O3 hollow nanotubes (Mn-In2O3) by solvothermal and annealing route using In-MOFs as precursors. The experimental results indicate that the obtained products possess hollow nanotube structures with plenty of holes and Mn doping greatly boosts the gas-sensing performance of In2O3-based sensors towards H2. In particular, the responses of 3 mol% Mn-In2O3 are 2.57 and 2.3 towards 50 ppm H2 at 360 °C and 400 °C, respectively, which are much higher than those of bare In2O3 hollow nanotubes. Besides, the sensor based on 3 mol% Mn-In2O3 exhibits a low limit of detection (25 ppb), excellent selectivity, rapid response/recovery speed (∼4 and ∼15 s@20 ppm), and excellent stability at high temperature (360 °C). Such enhancement of H2-sensing properties can be put down to the hollow structure derived from In-MOFs and abundant oxygen vacancy defects produced by Mn doping. The Mn-In2O3 hollow nanotubes could be regarded as promising materials for selectively detecting H2 in a wide range of concentrations.

A piezoelectric vibration sensor with excellent performance based on Bi12SiO20 crystal for high-temperature applications

High-temperature piezoelectric vibration sensors play a crucial role in the accurate monitoring of the dynamic mechanical conditions in aerospace, automotive, and energy generation systems. However, the use of conventional piezoelectric materials in high-temperature environments is restricted owing to their limited Curie temperatures. In this study, we grew a piezoelectric crystal Bi12SiO20 (BSO) with the crystal cut optimized for high longitudinal piezoelectric coefficient and low piezoelectric crosstalk behaviors. Subsequently, a compression-type piezoelectric vibration sensor utilizing the BSO bulk crystal was developed and fabricated for structural health monitoring under high temperatures. The impact of pre-tightening torques on the sensor performance was investigated. Moreover, the sensor performance was analyzed under temperatures up to 650 °C. The BSO-based sensor exhibited an average sensitivity of ∼3.89 pC/g between 25 and 650 °C under 160 Hz frequency, with a variation of 5.5%. Additionally, the BSO-based sensor demonstrated ultra-stable sensitivity at 600 °C, highlighting its strong sensing capabilities and reliability under high temperatures. Thus, the BSO-based vibration sensor is a promising option for structural health monitoring applications under high temperatures.

Electrical Properties of Textured Bismuth Layer-Structured Ferroelectric Ceramics with Large Number of Layers (m = 5)

Bismuth layer-structured ferroelectrics (BLSF) ceramics are attractive materials for high temperature sensor applications, because of their high Curie temperature Tc (300–900 °C), and the large anisotropy of their electromechanical coupling factor kt/kp or k33/k31. In this study, BLSF ceramics with a large number of layers, namely, (K0.5Bi0.5)2Bi4Ti5O18 + MnCO3 0.3 wt%+ Bi2O3 0.025 wt% (KBT5) and Sr0.75Ca0.25Na0.5Bi4.5Ti5O18 + CeO2 1 wt% [(SC)NBT5] ceramics, were prepared by ordinary firing (OF) and hot forging (HF) methods, and their electrical and piezoelectric properties were examined. Both KBT5 and (SC) NBT5 ceramics showed high Tc values of 545 and 424 °C, respectively. The OF-KBT5 ceramic had an electromechanical coupling factor k33 of 0.14 and a piezoelectric constant d33 of 20 pC/N, whereas the HF-KBT5 ceramic had k33 of 0.17 and d33 of 31 pC/N. On the other hand, the OF-(SC) NBT5 ceramic had k33 of 0.13 and d33 of 17 pC/N, whereas the HF-(SC) NBT5 ceramic had k33 that increased to 0.32 and d33 to 41 pC/N. The k33 and d33 of the HF ceramics were improved compared with those of the OF ceramics. Thus, the KBT5 and (SC) NBT5 ceramics with oriented grains were shown to have good piezoelectric properties with high Tc.

Rare-earth praseodymium-substituted Bi5Ti3FeO15 exhibiting enhanced piezoelectric properties for high-temperature application

Owing to their exceptional piezoelectric effects, piezoelectric materials play a crucial role in high-end technologies and contribute significantly to the national economy. Bismuth layer-structured ferroelectrics (BLSFs) possess high Curie temperatures, making them a focal point of research in high-temperature piezoelectric sensor devices. However, their poor piezoelectric performance and low direct-current (DC) electrical resistivity hinder their effective deployment in high-temperature applications. To overcome these shortcomings, we employed composition optimization by partially substituting bismuth ions with rare-earth praseodymium ions. This approach enhances the piezoelectric performance and improves the DC electrical resistivity by preventing the loss of volatile bismuth ions and stabilizing the bismuth oxide layer (Bi2O2)2+, thereby reducing the concentration of oxygen vacancies. Consequently, we achieved a large piezoelectric constant d33 of 23.5 pC/N in praseodymium-substituted Bi5Ti3FeO15, which is three times higher than that of pure Bi5Ti3FeO15 (7.1 pC/N), along with a high Curie temperature TC of 778 °C. Additionally, the optimal composition of 4 mol% praseodymium-substituted Bi5Ti3FeO15 exhibits good thermal stability of electromechanical coupling characteristics up to 300 °C. This study holds promise for a wide array of high-temperature piezoelectric applications and has the potential to accelerate the development of high-temperature piezoelectric sensor technologies.

Enhancing electrical properties of SiHfBCN ceramics through Cu-catalyzed polymer-derived ceramic synthesis

In this study, we employed Cu-catalyzed polymer-derived ceramic methods at lower temperatures to synthesize SiHfBCN ceramics. The SiHfBCN-Cu single-source precursors were characterized using Fourier Transform-Infrared Spectrometry and thermal gravimetric analysis, while X-ray diffraction, X-ray photoelectron spectroscopy, Raman Spectrometer, transmission electron microscopy, and a four-point probe setup were utilized to investigate composition, microstructural evolution, and electrical conductivity. Our analysis revealed that the electrical conductivity of SiHfBCN-Cu ceramics, annealed at 1500 °C, reached an impressive 2409.6 S·m-¹. This improvement was attributed to the influence of pyrolysis temperature and Cu content, resulting in the formation of in-situ abundant graphite-like carbon, Cu nano crystallites and Hf1-xCuxC@C and SiC@C nanoparticles with core-shell structures constructed a three-dimensional conductive network. Importantly, Cu-catalyzed SiHfBCN ceramics at lower temperatures produced an abundance of graphite-like carbon ribbons, effectively enhancing their electrical conductivity. These findings highlight the potential of Cu-catalyzed SiHfBCN ceramics as high-temperature sensors for in-situ measurements in extreme environments.

Construction of a High-Temperature Sensor for Industry Based on Optical Fibers and Ruby Crystal.

This paper presents the construction of an innovative high-temperature sensor based on the optical principle. The sensor is designed especially for the measurement of exhaust gases with a temperature range of up to +850 °C. The methodology is based on two principles-luminescence and dark body radiation. The core of this study is the description of sensing element construction together with electronics and the system of photodiode dark current compensation. An advantage of this optical-based system is its immunity to strong magnetic fields. This study also discusses results achieved and further steps. The solution is covered by a European Patent.

In situ conductometry for studying the homogenization of Al-Mg-Si alloys and predicting extrudate grain structure through machine learning

In industrial practice, no sensors capable of obtaining microstructural information in situ during thermo-mechanical processing of Al alloys are commonly employed. Inductive electrical conductivity measurement is safe, inexpensive, and capable of acquiring valuable information about precipitation and dissolution processes. However, commercial eddy current sensors work only at low temperatures near room temperature and are thus not suitable for in situ conductometry during heat treatments of Al alloys. We designed a high-temperature eddy current sensor and performed in situ conductometry during the homogenization of six Al-Mg-Si wrought alloys, three of which are experimental recycling-friendly alloys with increased Fe content. The results are interpreted with regard to microstructural investigations, and the advantages and limitations of our approach are discussed. As a proof-of-concept, we show how the conductivity curves and extrusion process parameters can be combined to predict final extrudate grain structures using machine learning. To achieve this, we employed finite element simulation of extrusion coupled with microstructural simulation over a wide parameter range, validated by extrusion experiments and metallography, and trained a feedforward neural network. We believe our interdisciplinary approach can lead to improvements in the industrial processing of Al wrought alloys.

High-Entropy CeNbO4+δ-Based Ceramics with Ultrahigh Comprehensive Thermosensitive Performances.

Next-generation advanced high-temperature sensors rely heavily on negative temperature coefficient thermosensitive ceramics with low cost, small volume, high sensitivity, and fast response. However, thus far, the enormous challenge of achieving ultrahigh stability and accuracy has become a critical bottleneck restricting the development of thermosensitive ceramics in high-temperature sensor applications. Here, we propose a high-entropy strategy to design a "cation valence self-equilibrium" system in CeNbO4+δ-based ceramics introducing redox couple compensation and ultrahigh density dislocations to solve the problem of temperature-dependent oxygen nonstoichiometry that restricts the performances of high-temperature thermosensitive ceramics. Ferroelastic domains are generated by enhancing the configurational entropy at both A and B sites, resulting in a dramatic increase of dislocation density to >1010 mm-2, which ultimately optimizes the thermosensitive performances. Extreme temperature measurement accuracy with R2 as high as 999.98‰ and RSS as low as 0.011 and high-temperature stability with ΔR/R0 as low as 0.23% after aging at 873 K for 1000 h are realized in high-entropy CeNbO4+δ-based ceramics, indicating a breakthrough in the comprehensive performances of thermosensitive ceramics. This work opens up an effective way to design thermosensitive materials with ultrahigh comprehensive performance to meet the requirements of advanced high-temperature sensors.

Printable silicate and RuO2 composite with wide-range linear PTC for high-temperature sensors

3D printing has revolutionised the design and manufacturing of high-temperature thin/thick-film sensors (TFSs). However, existing printable high-temperature materials face cost-performance trade-offs. This study proposes a silicate and RuO2 composite for the 3D printing of TFSs. A silicate compound (SiO2–Al2O3–CaO, SAC) was used as a sintering aid to reduce the sintering temperature of RuO2, forming a silicate glass phase that enhanced film density and substrate adhesion. The SAC also minimised RuO2 particle volatilisation at high temperatures, thus enhancing the stability of the SAC/RuO2 composite. The SAC/RuO2 TFSs demonstrated exceptional performance, with a positive temperature coefficient (502 ppm/°C) from room temperature to 800 °C, high linearity, and stability (resistance drift rate of 0.1 %/h at 800 °C), extending the application temperature of RuO2 by nearly 200 °C from the previous application temperature of 600 °C. Therefore, the SAC/RuO2 composite offers a new low-cost and high-performance solution for using 3D printing technology in harsh environmental sensors such as turbine blades.

Langasite-based SAW high-temperature vibration sensor with temperature decoupling

Langasite-based SAW high-temperature vibration sensor with temperature decoupling

Innovative coaxial high-temperature thin-film sensor with core–shell structure surpassing traditional multilayer films

Innovative coaxial high-temperature thin-film sensor with core–shell structure surpassing traditional multilayer films

Single-photon detection using large-scale high-temperature MgB2 sensors at 20 K

Ultra-fast single-photon detectors with high current density and operating temperature can benefit space and ground applications, including quantum optical communication systems, lightweight cryogenics for space crafts, and medical use. Here we demonstrate magnesium diboride (MgB2) thin-film superconducting microwires capable of single-photon detection at 1.55 μm optical wavelength. We used helium ions to alter the properties of MgB2, resulting in microwire-based detectors exhibiting single-photon sensitivity across a broad temperature range of up to 20 K, and detection efficiency saturation for 1 μm wide microwires at 3.7 K. Linearity of detection rate vs incident power was preserved up to at least 100 Mcps. Despite the large active area of up to 400 × 400 μm2, the reset time was found to be as low as ~ 1 ns. Our research provides possibilities for breaking the operating temperature limit and maximum single-pixel count rate, expanding the detector area, and raises inquiries about the fundamental mechanisms of single-photon detection in high-critical-temperature superconductors.

Multifunctional Nanocomposite Yield-Stress Fluids for Printable and Stretchable Electronics.

Compliant materials are crucial for stretchable electronics. Stretchable solids and gels have limitations in deformability and durability, whereas active liquids struggle to create complex devices. This study presents multifunctional yield-stress fluids as printable ink materials to construct stretchable electronic devices. Ionic nanocomposites comprise silica nanoparticles and ion liquids, while electrical nanocomposites use the natural oxidation of liquid metals to produce gallium oxide nanoflake additives. These nanocomposite inks can be printed on an elastomer substrate and stay in a solid state for easy encapsulation. However, their transition into a liquid state during stretching allows ultrahigh deformability up to the fracture strain of the elastomer. The ionic inks produce strain sensors with high stretchability and temperature sensors with high sensitivity of 7% °C-1. Smart gloves are further created by integrating these sensors with printed electrical interconnects, demonstrating bimodal detection of temperatures and hand gestures. The nanocomposite yield-stress fluids combine the desirable qualities of solids and liquids for stretchable devices and systems.

An amperometric high-temperature ammonia sensor based on a BaCo0.4Fe0.4Zr0.1Y0.1O3-δ triple conductor

Selective catalytic reduction (SCR) utilizing urea hydrolysis to generate ammonia (NH3) is the most efficient technology to reduce the emission of nitrogen oxides (NOx). NH3 detection is crucial in the closed-loop feedback system for the precise urea injection. In this work, a high-temperature NH3 sensor using a BaZr0.8Y0.2O3-δ (BZY) proton conductor as the electrolyte and a BaCo0.4Fe0.4Zr0.1Y0.1O3-δ (BCFZY) H+/e–/O2– triple conductor as the sensing electrode (SE) is reported. The effect of the micromorphology of the BCFZY SE on the sensing performance is investigated by varying the sintering temperature of SE. The sensor shows high sensitivity to NH3 with response currents of 0.39, 1.31, 3.03, and 1.81 μA/ppm at 350, 400, 450, and 500 °C, respectively. Furthermore, the sensor shows excellent selectivity and repeatability. This work demonstrates that the BCFZY-based sensor has great potential for the high-temperature NH3 detection.