Wide-range Temperature Sensor Research Articles

Wide-range and ultra-low temperature thermometer based on a silicon resonator.

In this Letter, the silicon-based microring resonator (MRR) was experimentally demonstrated for cryogenic sensing down to 10 K by overcoming the issue of acquiring the optical signals at low temperatures for on-chip optical sensors. A wide-range temperature sensor from 240 to 10 K was obtained. The experimental results show that the device sensitivity decreased from 64.7 pm/K at 240 K to 4.19 pm/K at 10 K. Theoretical analysis indicates that the reduction in sensitivity is attributed to the weakening of thermo-optic effects with the decrease in temperature, which is well consistent with the experimental results. Based on this work, the silicon-based ring resonators, featuring complementary metal oxide semiconductor (CMOS) compatibility, high-quality factors, and ease of chip-scale integration, are a potential platform for ultra-low temperature monitoring.

Wide-range soft anisotropic thermistor with a direct wireless radio frequency interface

Temperature sensors are one of the most fundamental sensors and are found in industrial, environmental, and biomedical applications. The traditional approach of reading the resistive response of Positive Temperature Coefficient thermistors at DC hindered their adoption as wide-range temperature sensors. Here, we present a large-area thermistor, based on a flexible and stretchable short carbon fibre incorporated Polydimethylsiloxane composite, enabled by a radio frequency sensing interface. The radio frequency readout overcomes the decades-old sensing range limit of thermistors. The composite exhibits a resistance sensitivity over 1000 °C−1, while maintaining stability against bending (20,000 cycles) and stretching (1000 cycles). Leveraging its large-area processing, the anisotropic composite is used as a substrate for sub-6 GHz radio frequency components, where the thermistor-based microwave resonators achieve a wide temperature sensing range (30 to 205 °C) compared to reported flexible temperature sensors, and high sensitivity (3.2 MHz/°C) compared to radio frequency temperature sensors. Wireless sensing is demonstrated using a microstrip patch antenna based on a thermistor substrate, and a battery-less radio frequency identification tag. This radio frequency-based sensor readout technique could enable functional materials to be directly integrated in wireless sensing applications.

Soliton microcomb-assisted microring photonic thermometer with ultra-high resolution and broad range

Whispering gallery mode resonators (WGMRs) have proven their advantages in terms of sensitivity and precision in various sensing applications. However, when high precision is pursued, the WGMR demands a high-quality factor usually at the cost of its free spectral range (FSR) and corresponding measurement range. In this article, we propose a high-resolution and wide-range temperature sensor based on chip-scale WGMRs, which utilizes a Si3N4 ring resonator as the sensing element and a MgF2-based microcomb as a broadband frequency reference. By measuring the beatnote signal of the WGM and microcomb, the ultra-high resolution of 58 micro-Kelvin (μK) was obtained. To ensure high resolution and broad range simultaneously, we propose an ambiguity-resolving method based on the gradient of feedback voltage and combine it with a frequency-locking technique. In a proof-of-concept experiment, a wide measurement range of 45 K was demonstrated. Our soliton comb-assisted temperature measurement method offers high-resolution and wide-range capabilities, with promising advancements in various sensing applications.

Solvent-free adhesive ionic elastomer for multifunctional stretchable electronics

Intrinsically stretchable and transparent ionic conductors are of great interest due to their promising applications in flexible and wearable electronics. However, hydrogels/organogels based devices suffer from instability due to liquid evaporation or leakage. Herein, we present a solvent-free ionic elastomer (IE), featuring high transparency (>92%), stretchability (300%), ionic conductivity (0.07 mS/cm), adhesiveness (61 N/m), thermal stability (300 °C), and negligible mechanical hysteresis, which endows implementation capacity in multifunctional stretchable electronics. The IE-based robust strain sensors (both resistive and capacitive) show linear sensitivities in the range of 0–150% strain and long-term stability. Moreover, a reversible wide-range temperature sensor is presented showing remarkable sensitivity in the range of 30–55 °C sustained under 50% stretching. The temperature-strain effect on the IE-based sensor is insignificant, ensuring an accurate sensing capability. Thanks to its self-adhesiveness, a fully integrated, stretchable motion energy harvester as well as a skin-like thin triboelectric sensor array using IE as the electrode are further designed to demonstrate efficient human motion energy harvesting with a peak power density of 3.6 W/m2 and self-powered tactile sensing. The results provide strategies towards potential applications of developed IE in healthcare monitoring systems, biomechanical energy harvesting, soft robotics, and human-machine interfaces.

Highly-sensitive and wide-range temperature sensor based on polymer-filled micro-cavity in fibre Bragg grating by temperature segmentation

A highly-sensitive and wide-range temperature sensor based on a polymer-filled Mach-Zehnder (MZ) micro-cavity in commercial fibre Bragg grating (FBG) was proposed. The micro-cavity was fabricated rightly across half of the fibre core at the FBG position by using femtosecond laser micromachining, and then it was filled with the polymer with high thermo-optical coefficient. A temperature segmentation demodulation method was presented by monitoring the MZ peak and FBG peak in the transmission spectrum synchronously, which expanded the temperature measurement range to more than 80 °C with ultra-high sensitivity (9.33 nm/°C) and perfect linearity.

A langasite surface acoustic wave wide-range temperature sensor with excellent linearity and high sensitivity

Langasite (LGS) surface acoustic wave (SAW) temperature sensors have a large second order temperature coefficient of frequency, which leads to their non-linear and non-monotonic responses in a wide temperature range and possibly makes the measured temperatures non-unique for a specific sensor response. Here, we propose a high-temperature Pt/LGS SAW sensor with linear frequency–temperature behavior in a wide temperature range, which was fabricated on a LGS (0°, 138.5°, 72°) substrate. The sensor has a single acoustic mode, but dual resonances with similar second- and third-order temperature sensitivities that were utilized for achieving a linear frequency–temperature response by a method of difference. A linear relationship between the measured sensor output (Δfm21) and temperature was obtained in the range of −60 °C to 700 °C, consistent with the theoretical analysis. The sensor has a high sensitivity of −167 ppm/K for the whole temperature range. All the results demonstrated exciting prospects of the sensor for wide temperature monitoring in harsh environments.

Wide-range temperature sensor based on enhanced up-conversion luminescence in Er3+/Yb3+ co-doped Y2O3 crystal fiber

Abstract The Y2O3:Er3+/Yb3+ crystal fiber material has been successfully prepared by laser heated pedestal growth method. The X-ray diffraction results indicate that the prepared Y2O3:Er3+/Yb3+ luminescent material, which is optically transparent under the optical microscope, possesses pure Y2O3 crystal phase. The up-conversion luminescence corresponding to the (2H11/2, 4S3/2, 4F9/2) → 4I15/2 transitions of Er3+ ions were recorded under a 976 nm laser diode excitation. The up-conversion emission intensities from the 2H11/2 → 4I15/2 and 4S3/2 → 4I15/2 transitions of Er3+ ions were studied from room temperature to 873 K by fluorescence intensity ratio (FIR) technique. It has been found that the prepared Y2O3:Er3+/Yb3+ crystal fiber has high-efficient up-conversion emissions, and effectively improves the temperature measurement accuracy and range, making Y2O3:Er3+/Yb3+ crystal fiber an interesting candidate for optical temperature sensor.

NFC Powered Implantable Temperature Sensor.

Inductively powered 99% accurate implantable temperature sensor is designed, characterized and the findings are presented in this paper. The implantable sensors deliver a continuous temperature reading to external storage or readout devices via Near Field Communication interface. A 2.76μH rectangular inductive coil printed on a thin biocompatible plastic substrate is designed to establish the coupling link through NFC interface with external readout devices. A commercially available wide range temperature sensor chip is mounted along with the developed inductive coil on the same plastic substrate. For 50 samples, the received signal strength indicator, temperature accuracy and statistical distribution of measurement levels is investigated. Comparison of predetermined temperature in a controlled temperature and humidity chamber versus the temperature reading from the developed sensors proves a 99% accuracy.

Green Upconversion Emission of Yb3+/Er3+ co-doped Gd2Sn2O7 Nanophosphors as Wide-Range Temperature Sensor

Gd2Sn2O7:Yb3+/Er3+ (abbreviation for GSO: Yb3+/Er3+) nanophosphors codoped with Er3+ (0.1-2 at%) and Yb3+ (0.5-5 at%) were synthesized by a microwave hydrothermal process and annealed at 800 ℃ for 5 h. Powder X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy and upconversion emission spectra were used to characterize the as-synthesized sample. Under the irradiation of 980 nm laser diode, the GSO: Yb3+/Er3+ nanophosphors emitted green emissions centered at 525 and 546 nm (Er3+ :2H11/2→4I15/2 and 4S3/2→4I15/2 transition), red emissions centered at 659 and 677 nm (Er3+:4F9/2→4I15/2 transition). The temperature dependent emission intensity ratio of the thermally coupled levels (2H11/2/4S3/2) of Er3+ in the wide-range of 110-573 K was recorded to study the optical thermometric properties of GSO: Yb3+/Er3+ nanophosphors. The maximum sensitivity of GSO: Yb3+/Er3+ nanophosphors was approximately 36.34x10-4 K-1 at 466 K. This result indicates that GSO: Yb3+/Er3+ nanophosphors are potential candidates for wide-range optical temperature sensors with high sensitivity.

Ln3+ (Er3+, Tm3+ and Ho3+)-doped NaYb(MoO4)2 upconversion phosphors as wide range temperature sensors with high sensitivity

Well-crystallized NaYb(MoO4)2 doped with lanthanide ions (Ln3+: Er3+, Tm3+ and Ho3+) are successfully synthesized by hydrothermal method with further calcination. And the samples with different morphologies are obtained by changing the pH values and the molar ratio of Ln(NO3)3/Na2MoO4 of the resultant solutions. The upconversion (UC) luminescence spectra of NaYb(MoO4)2: Ln3+ between 323 K and 573 K under 980 nm excitation exhibit temperature-dependent property. The fluorescence intensity ratio (FIR) techniques with thermally coupled states (TCS) (Er3+: 2H11/2, 4S3/2 → 4I15/2, Tm3+: 1G4(1),(2) → 3H6, Ho3+: 5F5(1),(2) → 5I8) have high sensitivity (S) values (Er3+: 0.0122 K−1 at 548 K, Tm3+: 0.0025 K−1 at 323 K and Ho3+: 0.00035 K−1 at 323 K). The non-TCS (Ho3+: 5F5, 5S2/5F4 → 5I8) is used to extend the range of S, and the slope of FIR (non-TCS)-T is the S value as high as 0.02455 K-1 in the wide temperature range from 323 K to 573 K.

Wide range temperature sensor with adaptive nonlinearity cancellation (ANC) technique for HVICs

A new temperature sensor utilising an adaptive nonlinearity cancellation circuit is proposed among two base-emitter voltages (VBEPT and VBEIO) of the diode-connected bipolar junction transistors driven in saturation region with a proportional to absolute temperature current and an independent of absolute temperature current, respectively. In this way, the nonlinear effect originated from the temperature dependence of saturation current (IS) drift can be cancelled adaptively through subtraction circuits. The measurements indicate that the proposed temperature sensor can achieve a sensitivity of −9.75 mV/°C with linearity up to 99.95% over the temperature range of 170°C (−40–130°C).

Infrared-to-visible upconversion emission of Er3+/Yb3+-codoped SrMoO4 phosphors as wide-range temperature sensor

Er3+/Yb3+-codoped SrMoO4 phosphors were prepared by a high-temperature solid-state reaction method. At room temperature, all the as-prepared samples exhibited strong upconversion properties and the emission intensity increased dramatically with the increase of Yb3+ ion concentration, reaching its maximum value when the concentration was 5 mol%. The dependence of emission intensity on the pump power suggested that the upconversion emission was a two-photon process. Furthermore, the optical temperature sensing properties based on green upconversion emissions of the SrMoO4:0.01Er3+/0.05Yb3+ phosphor were studied. It is found that the SrMoO4:0.01Er3+/0.05Yb3+ phosphor can be operated over a very wide temperature range of 93–773 K with a maximum sensitivity of ∼0.0128 K−1, indicating that low- and high-temperature thermometry can be simultaneously realized in this phosphor.

Analysis of Calibrated On-Chip Temperature Sensor With Process Compensation for HV Chips

This brief presents a wide-range temperature sensor with process compensation and nonlinear calibration for HV chip thermal monitoring. Due to a high supply voltage and a large current, HV chips are prone to overheating; thus, they require on-chip temperature sensors to monitor thermal variation. The voltage difference between the drain and source voltages of a metal–oxide–semiconductor, i.e., ${V}_{\rm DS} $ , of HV devices is enlarged by high supply voltages, causing a severe channel length modulation effect to jeopardize the linearity of the saturation current. The proposed calibrated temperature sensors in this brief provide a nonlinear calibration function to resolve this problem. Moreover, our design reveals a process compensation capability by the proposed process variation canceler. The maximal deviation in the range of $(-40 ^{\circ}\hbox{C}, +150) ^{\circ}\hbox{C}$ is measured to be $-2.05 ^{\circ}\hbox{C}$ – $+2.06 ^{\circ}\hbox{C}$ .

CdS : SiO2 nanocomposite as a luminescence-based wide range temperature sensor

A wide range (20–560 K) temperature sensor exhibiting linear behavior in entire range is devised from CdS:SiO2 nanocomposite with average sensitivity and resolution ≈10−2 K−1 & 10−4 K respectively and maximum relative sensitivity ~8.4% K−1 at 120 K.​

Wide Range Temperature Sensors Based on One-Dimensional Photonic Crystal with a Single Defect

Transmission characteristics of one-dimensional photonic crystal structure with a defect have been studied. Transfer matrix method has been employed to find the transmission spectra of the proposed structure. We consider a Si/air multilayer system and refractive index of Si layer has been taken as temperature dependent. As the refractive index of Si layer is a function of temperature of medium, so the central wavelength of the defect mode is a function of temperature. Variation in temperature causes the shifting of defect modes. It is found that the average change or shift in central wavelength of defect modes is 0.064 nm/K. This property can be exploited in the design of a temperature sensor.

Analysis of Er 3+ and Ho 3+ codoped fluoroindate glasses as wide range temperature sensor

The fluorescence intensity ratio technique for two fluoroindate glass samples has been carried out. The green emissions at 523 nm and at 545 nm in a 0.1 mol% of Er 3+ doped fluoroindate glass was studied in a wide range of temperature from 125 K to 425 K with a maximum sensitivity of 0.0028 K −1 for 425 K. In a sample doped with 0.1 mol% of Ho 3+ the emissions at 545 nm and at 750 nm were analyzed as a function of temperature from 20 K to 300 K obtaining a maximum sensitivity of 0.0036 K −1 at 59 K. Using both fluoroindate glass samples a wide temperature range from 20 K to 425 K is easily covered pumping with two low-cost diode laser at 406 nm and 473 nm.

Metal-Containing Diamond-Like Nanocomposite Thin Film for Advanced Temperature Sensors

The conductivity of metal-carbon-silicon nanocomposite films considered as potential candidates for the application as wide-range temperature sensors for severe environmental conditions is studied. The films combine unique properties of amorphous carbons with a new functionality imparted by the presence of metal nanoclusters in host matrix. The deposition of carbon-silicon phase was performed using PECVD of siloxane vapors. Metals (W, Nb, and Cr) with concentration in the range from 12 to 40 at. % were incorporated in the carbon-silicon host matrix by DC magnetron co-sputtering. The conductivity of the films decreases with temperature in the range 80-400 K, being well described by the power-law dependence. The conductivity mechanism found satisfactory explanation in the framework of the model of inelastic tunneling of electrons between metal nanoclusters dispersed in carbon-silicon matrix. The parallel study of the influence of metal concentration increase on carbon phase microstructure was carried out using Raman spectroscopy.

Metal-containing diamond-like nanocomposite temperature sensors

Metal-carbon nanocomposites are characterized by a number of unique properties, perspective for the various-type sensor applications. Presented experimental data of the conductivity of amorphous tungsten- and niobium-containing carbon-silicon nanocomposite films show the possibility to design the advanced wide-range temperature sensors, which are expected to possess the chemical stability, biocompatibility, mechanical, and other properties typical for this class of materials. The investigated films were deposited onto polycrystalline substrates using combination of Plasma Enhanced Chemical Vapor Deposition (PECVD) of siloxane vapors and DC magnetron co-sputtering of metal target. The conductivity σ of the films, measured using standard 4-probe technique in the temperature range 80-400K, is characterized by the gradual decrease with temperature. The experimental σ(T) dependences are well fitted by the power-law expression, σ(T) = σ0+aTn, where σ0, a, and n are the fitting parameters dependent on the type of metal and the value of metal concentration. The electron transport mechanism in the investigated amorphous metal-containing carbon-silicon nanocomposite films is discussed in the framework of the model of inelastic tunneling of electrons in amorphous insulators in the presence of the structural transformation in the carbon-silicon host matrix. The evolution of the structure of the carbon phase by metal concentration increase was studied by Raman spectroscopy.

DLC硬質膜を用いた温度センサの機能性評価(J09-6 プロセス,J09 知的材料・構造システム)

This paper describes the possibility of Me-DLN films as temperature sensor. DLC is used as coating material for the cutting tools up to now. The problem is low adherence between film and substrates. In order to solve it DLN was proposed. In this study Metal-containing DLN was deposited onto ceramics substrate by DC and RF discharged of siloxane vapor. During deposition metal phase was fabricated by magnetron sputtering of metal target. Temperature-conductivity dependence was measured by standard 4-terminal method in the temperature range of 80-400 K in vacuum. Dimensionless temperature sensitivity of investigated films are calculated as a evaluation of temperature sensors. All films are demonstrated weak temperature dependence of conductivity and calculation of dimensionless temperature sensitivity show that Me-DLN has a possibility to be used as wide range temperature sensors. And Me-DLN temperature sensors are hoped to have not only the properties of coating materials but also sensing function.

Metal-containing diamond-like carbon-silicon nanocomposite films as temperature sensors

ABSTRACTMetal-carbon nanocomposites are characterized by a number of unique properties, perspective for the various-type applications. The presented experimental data on the conductivity of amorphous tungsten- and niobium-containing carbon-silicon nanocomposite films show the possibility of the design of advanced wide-range temperature sensors, which are expected to possess the chemical stability, biocompatibility, mechanical, and other properties typical for this class of materials. The films were deposited onto polycrystalline substrates using combination of PECVD(Plasma Enhanced Chemical Vapor Deposition) of siloxane vapors and magnetron co-sputtering of metal target. The conductivity σ of the films, measured using standard 4-probe technique in the temperature range 80–400K, is characterized by the gradual decrease with temperature. The experimental σ(T) dependences are well fitted by the universal power expression, σ(T)= σ0+aTn, where σ0, a, and n are the fitting parameters dependent on the value of metal concentration. The conductivity mechanisms in the investigated amorphous metal-containing carbon-silicon nanocomposite films are discussed in the framework of the model of inelastic tunneling in amorphous insulators in the presence of the structural transformation in carbon-silicon matrix.