High Pressure Sensor Research Articles

Highly Conductive Paths in Diamond and their Application in High Pressure Measurements.

Diamonds possess exceptional properties such as high mechanical strength, thermal conductivity, and electrical resistance, making them suitable for various applications, including high-power electronics and optoelectronics. However, fabricating conductive structures in diamond remains a significant technological challenge. In this publication, we present a controlled process for fabricating precise amorphous conductive paths in a monocrystalline diamond using a focused ion beam (FIB) technique. The resistivity and thickness of the fabricated structures were determined, and their morphology was carefully characterized. The results showed that the optimal charge dose for achieving the lowest resistance was found to be 1017 ions/cm2. The fabricated structures exhibited amorphous morphology. Elemental analysis confirmed the presence of gallium ions in the modified material. The resistivity of the conductive paths was determined to be 30 μΩm, which is remarkably low compared to previous studies and only 1-2 orders of magnitude higher than in metals. Additionally, it is shown that this technology has potential applications in high-pressure chambers and the development of high-pressure sensors within diamond anvils. Overall, this study provides valuable insights into fabricating conductive structures on diamonds using FIB and opens up possibilities for diamond electronics.

High sensitivity optical pressure sensor based on graphene/molybdenum disulfide composite film.

In this paper, a high sensitivity optical pressure sensor based on a graphene/molybdenum disulfide (MoS2) composite film is proposed. The sensor is composed of a polydimethylsiloxane (PDMS) pyramid structure, graphene/MoS2 composite film, and lithium niobate waveguide. The pressure deforms the PDMS pyramid structure, which leads to the change of the refractive index of the graphene/MoS2 composite film, and finally be detectable sensitively by the variation of the interference spectrum. Experiments have been carried out using our sensor prototype, and the sensitivity is up to 575.233 nm/kPa in the pressure range of 0 kPa-0.123 kPa, which is much higher than that of typical optical pressure sensors. This shows the advantages of high sensitivity optical pressure sensors based on the graphene/MoS2 composite film, which is expected to be applied in highly sensitive pressure detection environments.

High sensitivity gas pressure and temperature optical sensors based on tapered no-core fiber coated with polydimethylsiloxane (PDMS)

This article introduces a novel high-sensitivity pressure and temperature sensor utilizing a tapered no-core fiber (NCF) structure created by splicing the NCF with a single-mode fiber (SMF) to form a “SMF-NCF-SMF” structure, tapering the NCF, and applying a polydimethylsiloxane (PDMS) film on the tapered NCF surface. The experimental results show that the device with a diameter of 10 μm has a pressure sensitivity of 86.63 nm/MPa within one to two atmospheres. Furthermore, the temperature sensitivity is −1.97 nm/°C from 30 °C to 60 °C. The sensor exhibits excellent stability and repeatability, and the PDMS film enhances the mechanical strength of the device, indicating promising potential for high-sensitivity pressure and temperature applications.

Harsh Environment-Tolerant, High Performance Soft Pressure Sensors Enabled by Fiber-Segment Structure and Plasma Treatment.

As the demand for specialized and diversified pressure sensors continues to increase, excellent performance and multi-applicability have become necessary for pressure sensors. Currently, flexible pressure sensors are primarily utilized in fields such as health monitoring and human-computer interaction. However, numerous complex extreme environments in reality, including deep sea, corrosive conditions, extreme cold, and high temperatures, urgently require the services of flexible devices. Here, a piezoresistive flexible pressure sensor based on expanded polytetrafluoroethylene/functionalized carbon nanotubes (EPTFE/FCNT) is proposed. Benefiting from the unique fiber-segment architecture, chemical stability, and strong chemical binding force between EPTFE and FCNT, the fabricated sensor exhibits remarkable sensing capabilities and can be employed in multifarious extreme environments. It demonstrates a sensitivity of 862.28kPa-1, a response time of 6-7ms, and a detection limit below 1Pa. Furthermore, it possesses a pressure resolution of 0.0018% under 111kPa and can withstand over 10,000 loading and unloading cycles under 1MPa. Additionally, the EPTFE/FCNT sensor retains its outstanding pressure response and work efficiency in extreme conditions such as an ultra-low temperature of -80°C, high temperature (200°C), acidic and alkaline corrosion, and underwater. These notable attributes enormously broaden the sensors' real-world application range.

Simultaneous measurement of temperature and pressure sensing technology based on double cavity matching in batteries

A compact sensor based on fiber Fabry-Pérot (FP) cavities dual-cavity matching technique cascaded with fiber Bragg grating (FBG) is proposed and demonstrated to measure pressure and temperature variations inside battery. The sensitivity amplification mechanism for two-parameter measurements is analyzed and a cased reference chamber scheme is designed. Low-cost, small-size, high-temperature and corrosion-resistant all-fiber-optic high sensitivity gas pressure sensors targeting the interior of energy storage batteries are fabricated and cascaded with FBGs to measure temperature parameters. The experimental results show that the sensor has a sensitivity of −26.8322 nm/MPa in a pressure range of 1.86 MPa, the gas pressure inside the battery and the temperature inside and outside the battery at different discharge rates of 1500mAH capacity monobloc batteries can be measured practically, directly and instantly. It has potential applications in detecting subtle pressure variations caused by gas precipitation inside the battery and in temperature measurement, and provides a new concept and a feasible technological path for the measurement of key parameters inside lithium-ion batteries.

Fabrication of flexible pressure sensor for human detection by direct-write printing concave surface

Flexible pressure sensor plays an important role in the field of human-computer interaction area due to its high flexibility and sensitivity. Convex surface of flexible electrodes provide an efficient way to enhance the sensitivity of flexible pressure sensors. However, facilely preparing controllable convex surface of flexible electrodes is still a challenge for obtaining high sensitive flexible pressure sensors. In this paper, direct-write print technique was utilized to prepare a concave structure surface with viscoelastic substrate, which could be used to prepare convex structure flexible electrode for fabricating highly sensitive flexible pressure sensors. Interaction between ink droplet and substrate was explored to generate a concave template, which could be controlled in spacing and diameter with printing spacing and nozzle diameter. Convex structure flexible surface could be prepared with the concave template, and then the convex structure flexible electrode could be realized with the evaporation of metallic silver on the surface. Furthermore, flexible pressure sensor was assembled with an interlocking structure by stacking two convex structure flexible electrodes in a face-to-face way, which could efficiently enhance flexibility and electrical property. The flexible pressure sensor presents a high sensitivity, a fast response/recovery time (<100 ms) and excellent flexibility (more than 10,000 cycles of bending), which could be applied in monitor physiological signals such as pulse detection, sound vibration, finger bending and so on. Therefore, this work provides an efficient method for preparing controllable structured surface, which has a great potential in the fabrication of flexible sensors, wearable electronics and energy devices.

High pressure sensor based on intensity-variation using polymer optical fiber

Silica fiber under high pressure increases the risk of fiber breakage or permanent deformation, which may cause sensor failure due to mechanical strength limitations. High pressure can also induce birefringence in optical fiber. In this study, we present a simple design and low-cost high pressure sensor using polymer optical fiber (POF) based on the intensity-variation technique. A side-coupling mechanism in the sensor structure is adopted, which varies the intensity with applied pressure. Two POFs are twisted together to create a sensing region where the light is launched in the first fiber and measurement is taken from the second fiber. In sensing phenomena, cladding mode frustrated total internal reflection occurs when pressure increases. Silicone gel is used in the pressure chamber for sealing and preventing leakage. The sensor structure is able to detect high pressure in the MPa range, where we tested up to 4 MPa. For higher sensitivity, twisted and bend structure is analyzed, and sensitivity is achieved at about 432.21 nW/MPa. However, twisted helical structure is adopted to enhance sensing range which is about 50 cm. The proposed high-pressure sensor structure is easier to fabricate and has high stability because it doesn’t require any destructive method as compared to other conventional methods.

Rapid response, superior stable, and durable pressure sensor with rGO/CNC interdigital electrode

The development of pressure sensors with swift responsiveness and exceedingly high stability is an inevitable requirement for wearable electronic devices. Herein, we fabricated a high performance pressure sensor through the encapsulation of an interdigital electrode with employing polydimethylsiloxane (PDMS). The pressure sensor comprised self-assembled multifunctional reduced graphene oxide/cellulose nanocrystalline (rGO/CNC) composite film with interdigital electrode (RCI), and involves the use of PDMS to enhance the robustness and pressure sensitivity of the pressure sensor. The sensing enhancement is reflected in minimal conductive attenuation, under 30 min ultrasonic with a ΔR/R0 < 0.1 % in the initial phase and an impressive response time of 51 ms. Due to the outstanding performance, a smart glove that is integrated with the RCI sensor not only performs well timely feedback on human motions, but also achieves intelligent recognitions of various gestures assisted by neural network algorithms (the accuracy up to 99.1 %). Furthermore, this study offers an innovative decoupling method that effectively separates contact interface resistance and body resistance. The developed piezoresistive sensor and decoupling method are meaningful and valuable to long-term intelligent health management and human–machine interactions applications.

Ultra-broad sensing range, high sensitivity textile pressure sensors with heterogeneous fibre architecture and molecular interconnection strategy

Textile-based pressure sensors have garnered extensive attentions owing to their potentials in health monitoring, human–machine interactions, wearable human–machine interfaces (HMIs) and soft robotics. High sensitivity over a broad sensing range are highly desired yet challenging for textile pressure sensors due to the incompressibility of matrix materials and the stiffening of microstructures. Herein, we developed a high performance pressure sensor based on the silk/3-Aminopropyltriethoxy-silane/titanium carbide (Silk/APTES/MXene) film. The silk is designed with heterogeneous fiber architecture, which enables rich and multi-level contact pattern and could compensate for the effect of structural stiffening. Furthermore, APTES molecules are used to enhance the interface bonding between MXene and silk, promoting the mechanical stability of the sensor. Benefiting from these advantages, the Silk/APTES/MXene sensor device is achieved with high sensitivity of 17.1 KPa−1 over an ultra-broad sensing range up to 3.3 MPa (R2 = 0.997), ultra-low detection limit (0.25 Pa), and low fatigue toughness after 5000 cycles loading and unloading. With these merits, we have demonstrated its capability for a series of human motion detection (such as foot movement detection, arm/wrist/finger bending, etc) and an overall accuracy of 95 % is obtained with the help of CNN-based convolution neural architecture. More significantly, we have built an entire intelligent human–machine dialogue system and a patient-audience dialogue system, from lip/sign language recognition to real-time screen display and final voice output.

Diamond-based HBAR as a high-pressure sensor

Features of an application of a High-overtone Bulk Acoustic Resonator (HBAR) as a high-pressure sensor have been considered. In this way, the second version of an integrated measurement system combining a Diamond Anvil Cell (DAC) and an HBAR operating in the microwave frequency band from 1.3 to 3.7 GHz was developed. A specific configuration of HBAR based on a piezoelectric layered structure as “Al/ASN/Mo/(100) diamond” was proposed. Two independent methods of pressure control were used to calibrate the embedded HBAR as a pressure sensor: a stress-induced shift of the diamond Raman line and the shift of the R1 luminescence line of Cr3+ in the ruby matrix. A stable correlation between the frequency shifts of the acoustic overtones in the HBAR, the shift of the diamond Raman line and the shift of the R1 line with a change in pressure applied to the W-gasket with embedded ruby particles was established in the range of 0 … 30 GPa. The sensitivity of an investigated sensor to the pressure variation was found to be equal 1ΔPΔff=4.8∙10-4GPa-1. The maximal value of 30 GPa obtained in a given work can be easily increased after a minor reconfiguration of the DAC. Considering the range of 0 − 5 GPa a proposed built-in DAC acoustoelectronic sensor has the better performance and sensitivity compared with known methods of a pressure measurement.

High Sensitivity Pressure Sensor Using Tandem Wheatstone Bridge for Low Pressures

High Sensitivity Pressure Sensor Using Tandem Wheatstone Bridge for Low Pressures

Ultrawide Sensing Range and High-Sensitivity Capacitive Pressure Sensor Based on Skeleton Dilution Strategies for Human Motion and Correction of Poor Body Posture

Ultrawide Sensing Range and High-Sensitivity Capacitive Pressure Sensor Based on Skeleton Dilution Strategies for Human Motion and Correction of Poor Body Posture

Nested‐Cell Architecture and Molecular Surface Modification Enabled 10 Megapascals Range High Sensitivity Flexible Pressure Sensors for Application in Extreme Environment

AbstractFlexible pressure sensors with high sensitivity over a broad sensing range are of great value in daily life and highly desired in various extreme environment, from human motion inspection to heavy industrial robots to high energy radiation and extremely cold/high temperature environments. However, it remains a significant challenge for a single pressure sensor to simultaneously possess high sensitivity and broad detection range due to the trade‐off between these two properties. Here, a high‐performance pressure sensor is developed based on flexible modified silicon rubber/functionalized carbon nanotube (MSR/FCNT). The designed nested‐cell architecture and molecular surface modification strategy endow the pressure sensor with high sensitivity (&gt;28 kPa−1) over 10 MPa sensing range, an ultralow detection limit (≈0.94 Pa), an ultrahigh pressure resolution (0.0075%) at a pressure of 3 MPa, and a low fatigue over 10 000 repetitive cycles even at an extremely high pressure of 5 MPa. Furthermore, the resulting sensor presents excellent durability after freezing at extreme cold temperature (−80 °C) as well as resistance to high temperature (200 °C) and high‐energy X‐ray radiation. The proposed nested‐cell architecture is a generic strategy for porous materials to achieve broad range high sensitivity.

Design of Double Conductive Layer and Grid-Assistant Face-to-Face Structure for Wide Linear Range, High Sensitivity Flexible Pressure Sensors.

Recently, flexible pressure sensors have drawn great attention because of their potential application in human-machine interfaces, healthcare monitoring, electronic skin, etc. Although many sensors with good performance have been reported, researchers mostly focused on surface morphology regulation, and the effect of the resistance characteristics on the performance of the sensor was still rarely systematically investigated. In this paper, a strategy for modulating electron transport is proposed to adjust the linear range and sensitivity of the sensor. In the modulating process, we constructed a double conductive layer (DCL) and grid-assistant face-to-face structure and obtained the sensor with a wide linear range of 0-700 kPa and a high sensitivity of 57.5 kPa-1, which is one of the best results for piezoresistive sensors. In contrast, the sensor with a single conductive layer (SCL) and simple face-to-face structure exhibited a moderate linear range (7 kPa) and sensitivity (2.8 kPa-1). Benefiting from the great performance, the modulated sensor allows for clear pulse wave detection and good recognition of gait signals, which indicates the great application potential in human daily life.

Ultrawide sensing-range, super durable and high-strength epoxy/carbon fiber composites sensor based on stress-induced structure

Nowadays, high-pressure sensors are broadly utilized in manufacturing and applications for ensuring safe production and preventing failures. However, present high-pressure sensors are mainly fabricated by high-strength metal and cement, which are too heavy or easy-corrosive to satisfy long-term usage. Polymer piezoresistive materials have great potential due to their stability and light weight, but achieving high strength and durability at the same time remains a serious challenge. In this work, a high-strength pressure sensor is fabricated by epoxy resin/carbon fiber (EP/CF) composite, where CF builds a conductive network as a reinforcing phase and EP provides a durable and light-weight base phase. The conductive mechanism based on stress-induced structure has been elucidated, and the performance of related sensors in various conditions is revealed. The lightweight (∼1.28 g/cm3) pressure sensor manifests a wide sensing response range from 22 kPa to 80 MPa. Moreover, the durability of this novel pressure sensor is verified by repeating loading and unloading at a high pressure of 10 MPa for more than 3500 cycles. Meanwhile, the high temperature and water resistance are furtherly confirmed, where EP/CF composites exhibits excellent cycling stability (10 MPa, >1000 cycles) after heating (100 °C) or soaking in water. Attributed to the comprehensive performance of high-strength, ultrawide detection range, durability and light weight, EP/CF composites are applied for road safety monitoring and deep-sea operation, showing wide application prospects in high-pressure monitoring field.

3D printing wide detection range and high sensitivity flexible pressure sensor and its applications

Piezoresistive flexible pressure sensors hold significant promise in various applications, including electronic skin, human-machine interaction, and health monitoring. Nevertheless, conventional piezoresistive flexible pressure sensors encounter challenges in achieving both high sensitivity and wide detection range, which remain unresolved. The design of a sensor's microstructure presents itself as an effective strategy for enhancing sensor performance. Microporous structure is a commonly employed microstructure that substantially enhances the sensor's detection range. However, flexible pressure sensors with microporous structures often exhibit low sensitivity which limits their applications. Consequently, this study introduces an innovative layered and microporous structure to upgrade flexible pressure sensor with high sensitivity as well as wide detection range. By integrating 3D direct writing printing technology with foaming materials, multi-walled carbon nanotubes are incorporated as conductive fillers to fabricate a piezoresistive flexible pressure sensor (PPS) featuring both microporous and 3D structures. This sensor exhibits high sensitivity (0.298 kPa−1), a wide detection range (25 Pa to 130 kPa), favorable response time, and durability, which can be applicable to robotic arms, smart gloves, and other devices requiring effective stress detection. This study unveils novel design concepts for a category of piezoresistive flexible pressure sensors that are compatible with high sensitivity and wide detection range requirements.

Tunable luminescence in pyrochlore Lu2Sn2O7:Eu3+ nanoparticles at elevated pressure

High pressure study is crucial in chemical, physical and materials sciences for understanding phase transitions, new phase evolution and in designing pressure sensors. Utilizing the high potential of pyrochlore as luminescent sensors and its structural diversity, Lu2Sn2O7:5.0%Eu3+ (LSOE) nanoparticles (NPs) have been synthesized using a hydrothermal method and characterized at ambient condition using x-ray diffraction (XRD), Raman spectroscopy and field emission scanning electron microscopy (FESEM). The reduced intensity of hypersensitive electric dipole transitions (5D0→7F2), reduction in average luminescence lifetime, and increase in symmetry around Eu3+ has also being observed in the LSOE NPs induced by the applied high pressure. The same is reflected in color tuning from red to orange to yellow on switching pressure from low to medium to high. Lifetime spectroscopy suggests that high pressure causes site-swapping of europium ion from Lu3+ to Sn4+, which triggers change in local symmetry around Eu3+. This work will pave a newer way of designing high pressure induced color tunable phosphor, high pressure sensor and need-based site engineering in pyrochlore compounds and their nanomaterials for high pressure applications.

High sensitivity capacitive flexible pressure sensor based on PDMS double wrinkled microstructure

High sensitivity capacitive flexible pressure sensor based on PDMS double wrinkled microstructure

Ultrawide linear range, high sensitivity, and large-area pressure sensor arrays enabled by pneumatic spraying broccoli-like microstructures.

Large-area pressure sensor arrays with a wide linear response range and high sensitivity are beneficial to map the inhomogeneous interface pressure, which is significant in practical applications. Here, we demonstrate a pneumatic spraying method to prepare large-area microstructure films (PSMF) for high performance pressure sensor arrays. The sprayed surface morphology is designable by controlling the spraying parameters. It is worth noting that the constructed "broccoli" like morphology with a swollen top and shrunken bottom inspired a new mechanism to enlarge the linear response range by decreasing the series resistance with pressure increasing. At the same time, the pneumatic sprayed "broccoli" has a rough surface due to droplet stacking, which reduces the initial current effectively. Hence, the sensor achieves a 10 000 kPa ultrawide linear response range with a high sensitivity (98.71 kPa-1), and low detection (5 Pa). The prepared sensor has a small static response error (4.4%) and 5000 cycle full-range dynamic response durability. Finally, the constructed sensor arrays can distinguish the pressure distribution in different ranges clearly, which indicates a great potential in health care, motion detection, and the tire industry.

High Sensitivity Micro Fiber Fabry Perot Pressure Sensor Based on Silicon MEMS Technology

High Sensitivity Micro Fiber Fabry Perot Pressure Sensor Based on Silicon MEMS Technology