Piezoresistive Pressure Sensor Research Articles

Scorpion-inspired multi-scale contact enabled multifunctional piezoresistive pressure sensor based on hybrid nanofiber decoration

Inspired by the slit organs of scorpions, an array narrow orifice configuration (ANOC) piezoresistive foam sensors are developed by decorating hybrid polypyrrole (PPy)/ carbon nanotubes (CNT) nanofibers on the foam strut. The developed ANOC composite foam exhibits a unique multi-scale contact sensing mechanism enabled by the macro-scale internal dome structures, the micro-scale struts of the porous foam, the nano-scale PPy/CNT hybrid conductive networks, and the nano-scale friction of the rough CNT/PPy hybrid nanofibers (NFs), which rendered the ANOC composite foam an ultra-high sensitivity of 1.8 kPa−1 at low pressure within 1.5 kPa. When used as a piezoresistive pressure sensor, the ANOC composite foam exhibits a wide detection range (0 %-70 %), fast response/recover time (120/90 ms), and long-term stability and fatigue resistance (over 80000 s), and demonstrated capability to monitor various human activities. A smart cushion integrated with an array of foam sensors can accurately identify the human sitting positions and posture rectifying. Moreover, owing to the highly porous conductive network and the doped ions, the ANOC composite foam can generate energy from saline water and serve as a water-induced energy generation (WIEG) device for direct energy supply. This research paves the way for the development of multifunctional high-performance.

3D fabric-based piezoresistive pressure sensor: design, preparation, performance and simulation

3D fabric-based piezoresistive pressure sensor: design, preparation, performance and simulation

Fiber/Yarn and Textile-Based Piezoresistive Pressure Sensors

Fiber/Yarn and Textile-Based Piezoresistive Pressure Sensors

Analysis of a novel 3C-SiC thin layer on silicon diaphragms for enhanced stress amplification in MEMS piezoresistive pressure sensors

Analysis of a novel 3C-SiC thin layer on silicon diaphragms for enhanced stress amplification in MEMS piezoresistive pressure sensors

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.

High-Yield Large-Scale Suspended Graphene Membranes over Closed Cavities for Sensor Applications.

Suspended membranes of monatomic graphene exhibit great potential for applications in electronic and nanoelectromechanical devices. In this work, a "hot and dry" transfer process is demonstrated to address the fabrication and patterning challenges of large-area graphene membranes on top of closed, sealed cavities. Here, "hot" refers to the use of high temperature during transfer, promoting the adhesion. Additionally, "dry" refers to the absence of liquids when graphene and target substrate are brought into contact. The method leads to higher yields of intact suspended monolayer chemical vapor deposition (CVD) graphene and artificially stacked double-layer CVD graphene membranes than previously reported. The yield evaluation is performed using neural-network-based object detection in scanning electron microscopy (SEM) images, ascertaining high yields of intact membranes with large statistical accuracy. The suspended membranes are examined by Raman tomography and atomic force microscopy (AFM). The method is verified by applying the suspended graphene devices as piezoresistive pressure sensors. Our technology advances the application of suspended graphene membranes and can be extended to other two-dimensional materials.

Carbonized derivatives derived from the complex of Fe/Ni bimetallic MOFs and phenolic resin for flexible piezoresistive sensors in motion capture and health monitoring

Based on the substantial high surface area and the chemical robustness inherent to metal–organic frameworks (MOFs), their integration into piezoresistive flexible pressure sensors presents significant potential. Nonetheless, the application of such sensors is impeded by the low conductivity of MOFs. In this work, we increased the conductivity of MOFs by carbonizing 2-aminoterephthalic acid iron-nickel metal–organic frameworks (Fe/Ni-MOFs) and introducing phenolic resins to protect the structure of Fe/Ni-MOFs. Piezoresistive flexible sensors were developed by embedding this carbonized derivative on the surface of PDMS films. The senrors showed a sensitivity of 198.51 kPa−1, broad operating pressure range (0–5 kPa), a fast response time (46 ms), a short recovery time (28 ms), and a high abrasion resistance. The flexible pressure device could be applied to monitor the finger motion and human pulses. Overall, these flexible high sensitivity devices demonstrate potential in the fields of wearable technologies, real-time health monitoring, and biomedical applications.

Advancing healthcare through piezoresistive pressure sensors: a comprehensive review of biomedical applications and performance metrics

Abstract Piezoresistive pressure sensors have transformed biomedical applications, enabling precise diagnostics and monitoring. This concise review explores the fundamental principles, key components, and fabrication techniques of piezoresistive pressure sensors, focusing on critical performance metrics such as sensitivity, accuracy, and response time. Biomedical design challenges, including biocompatibility and long-term stability, are examined, offering insights into solutions for optimal sensor integration. In diverse biomedical applications, piezoresistive pressure sensors play pivotal roles, from blood pressure monitoring to implantable medical devices. The paper emphasizes their versatility in enhancing patient care through continuous and accurate monitoring. Looking forward, the review discusses emerging trends and potential research directions, positioning piezoresistive pressure sensors as central contributors to the future of biomedical technology, promising improved patient outcomes and advanced healthcare delivery through precise and continuous monitoring.

Identification of Acoustic Sources on Antares Launch Pad Using Microphone Phased Array

A microphone phased array (MPA) was mounted in the vicinity of pad 0A of Mid-Atlantic Regional Spaceport located on NASA’s Wallops Flight Facility to identify the evolution of acoustic sources from hold-down to an elevation of ∼200 ft during the launch of an Antares rocket (Northrop Grumman [NG]-19). The MPA was equipped with 70 piezo-resistive dynamic pressure sensors, a visible-band and an infrared-band camera, and a two-axis accelerometer. The noise map demonstrated an effective use of the water injection system to attenuate noise from plume impingement on the pad. They also pointed out the outlet of the exhaust duct, through which the steam and plume mixture ejected out, to be the primary noise source during a significant interval of time. A comparison with prior such measurements during the maiden launch of the Antares vehicle in 2013 showed significant attenuation of noise sources during the NG-19 launch. A strong source caused by the impingement of plume on the pad surface during the 2013 launch was found to be attenuated in 2023. The results showed the utility of an MPA in quantifying the impact of changes made to a launch pad.

Neuron-astrocyte interaction-inspired percolative networks with metal microdendrites and nanostars for ultrasensitive and transparent electronic skins

Biological systems provide innovative designs for electronic devices, optimizing network configurations for high-performance signal transmission with minimal energy consumption. The brain, as one of the most complex biological structures, demonstrates efficient network design through the multiscale radial networks of neurons and astrocytes. Emulating these brain networks offers a blueprint for the development of ultrasensitive pressure sensors for electronic skin, aiming to provide a more intuitive and sensitive mode of interaction between humans and machines. Herein, we propose a neuromorphic percolative network inspired by neuron-astrocyte interactions for ultrasensitive pressure sensors employing metal microdendrites and nanostars. Electromechanical investigation through representative volume elements simulation reveals that the optimized arrangement of microdendrites and nanostars in the neuromorphic percolative system enhances the percolation threshold and probability. Following these simulation results, we developed a neuromorphic percolative polyurethane (NP-PU) matrix utilizing the metal microdendrite-nanostar networks. The augmented quantum tunneling effect in the NP-PU matrix was investigated through electrochemical impedance spectroscopy and capacitance analysis. The fabricated piezoresistive pressure sensor with the NP-PU matrix shows ultrahigh sensitivity (160.3 kPa−1) at a low pressure range and a low limit of detection resolution (4 Pa), enabled by multi-channel quantum tunneling in the metal particle networks. Furthermore, the sensor maintains excellent mechanical flexibility and high optical transparency (75.4 %), improving its efficacy in applications like electronic skin and force touch panel. Our study highlights the potential of leveraging biological system-inspired network designs for crafting advanced electronic devices.

Porous reduced graphene oxide@multi-walled carbon nanotubes/polydimethylsiloxane piezoresistive pressure sensor for human motion detection

With the rapid development of wearable electronic, smart robot and health monitoring, there is a growing focus on flexible piezoresistive pressure sensors. Herein, a new strategy is proposed to prepare flexible piezoresistive pressure sensor with porous polydimethylsiloxane (PDMS) sponge as matrix and reduced graphene oxide (rGO) and multi-walled carbon nanotubes (MWCNTs) for the construction of dual-conductive network. The sensor exhibited excellent overall sensing performances (pressure detection range of 0–200 kPa, sensitivity of 1.62 kPa−1 in 0–29 kPa and 0.41 kPa−1 in 29–65 kPa, response/recovery time of 61/40 ms and 22,000 loading-unloading cycles at 0–15 % compressive strain). Meanwhile, the sensor was able to normally work in the range of 30–100 °C and affected little by temperature. In addition, the sensor was successfully applied for detecting various human motions as well as music recognition and identification. The piezoresistive pressure sensor has great application prospect in wearable devices, health monitoring, and human-machine interaction.

Development of Highly Sensitive and Thermostable Microelectromechanical System Pressure Sensor Based on Array-Type Aluminum-Silicon Hybrid Structures.

In order to meet the better performance requirements of pressure detection, a microelectromechanical system (MEMS) piezoresistive pressure sensor utilizing an array-type aluminum-silicon hybrid structure with high sensitivity and low temperature drift is designed, fabricated, and characterized. Each element of the 3 × 3 sensor array has one stress-sensitive aluminum-silicon hybrid structure on the strain membrane for measuring pressure and another temperature-dependent structure outside the strain membrane for measuring temperature and temperature drift compensation. Finite-element numerical simulation has been adopted to verify that the array-type pressure sensor has an enhanced piezoresistive effect and high sensitivity, and then this sensor is fabricated based on the standard MEMS process. In order to further reduce the temperature drift, a thermodynamic control system whose heating feedback temperature is measured by the temperature-dependent structure is adopted to keep the working temperature of the sensor constant by using the PID algorithm. The experiment test results show that the average sensitivity of the proposed sensor after temperature compensation reaches 0.25 mV/ (V kPa) in the range of 0-370 kPa, the average nonlinear error is about 1.7%, and the thermal sensitivity drift coefficient (TCS) is reduced to 0.0152%FS/°C when the ambient temperature ranges from -20 °C to 50 °C. The research results may provide a useful reference for the development of a high-performance MEMS array-type pressure sensor.

High-performance flexible pressure sensors with bionic dome-shaped fold structures inspired by crocodile skin

Flexible pressure sensors have drawn substantial community interest as a result of the advancement of contemporary technology. Inspired by the unique sensory organs of crocodiles, an ordered bionic dome-shaped fold structure array was prepared using a facile process in this paper, and electrical experiments confirmed the enhancement of the capabilities of piezoresistive flexible pressure sensors. The results revealed that this type of flexible pressure sensor presented a sensitivity of 8.87 kPa−1, could withstand a maximum pressure of 60 kPa, a minimum detection pressure of 10 Pa, a response time of 70 ms, and maintained stable performance under 5000 repeated presses. In addition, the flexible pressure sensors based on dome-shaped fold structure arrays have been successfully applied for human signal detection and plantar pressure monitoring system. The current research has significant implications for the manufacturing and practical applications of highly effective flexible pressure sensors.

Temperature Compensation Method for Piezoresistive Pressure Sensors Based on Gated Recurrent Unit.

Piezoresistive pressure sensors have broad applications but often face accuracy challenges due to temperature-induced drift. Traditional compensation methods based on discrete data, such as polynomial interpolation, support vector machine (SVM), and artificial neural network (ANN), overlook the thermal hysteresis, resulting in lower accuracy. Considering the sequence-dependent nature of temperature drift, we propose the RF-IWOA-GRU temperature compensation model. Random forest (RF) is used to interpolate missing values in continuous data. A combination of gated recurrent unit (GRU) networks and an improved whale optimization algorithm (IWOA) is employed for temperature compensation. This model leverages the memory capability of GRU and the optimization efficiency of the IWOA to enhance the accuracy and stability of the pressure sensors. To validate the compensation method, experiments were designed under continuous variations in temperature and actual pressure. The experimental results show that the compensation capability of the proposed RF-IWOA-GRU model significantly outperforms that of traditional methods. After compensation, the standard deviation of pressure decreased from 10.18 kPa to 1.14 kPa, and the mean absolute error and root mean squared error were reduced by 75.10% and 76.15%, respectively.

Starfish-inspired ultrasensitive piezoresistive pressure sensor with an ultra-wide detection range for healthcare and intelligent production

Flexible pressure sensors have attracted significant attention due to their wide range of applications in various fields (e.g., robotis, healthcare, and human–machine interfaces). However, achieving both high sensitivity and a wide detection range remains a challenge. Here, we propose a novel starfish-inspired ultrasensitive piezoresistive pressure sensor capable of detecting an extensive range of pressures. The sensor’s design incorporates high and low spine structures inspired by the surface of a starfish, efficiently preventing rapid saturation of detection range and expanding the response range. Unlike single-material nanofiber structures, the ultrathin and ultrasensitive layer, fabricated using PEDOT: PSS/TPU nanofibers, possesses a large surface area ratio and numerous contact points. This allows for a quick increase in conductive channels when pressure is applied. The intertwining of PEDOT: PSS fibers with TPU fibers enhances both the mechanical strength of the fiber membrane and the initial resistance of the sensor, thereby increasing its sensitivity. Additionally, PVA fibers are fabricated over the interdigital electrode to serve as insulation layer for controlling resistance change between the sensitive layer and the electrode. Importantly, the interaction between the PVA fibers and the PEDOT: PSS/TPU fibers alters the deformation behavior of the sensitive layer fibers, further enhancing the performance of the sensor. The fabricated sensor demonstrates exceptional sensitivity (302.9 kPa−1), an extensive detection range of 0–426.7 kPa, and remarkable endurance of over 7,000 cycles at 110 kPa, rendering it a device with great potential for precise pressure sensing applications in health monitoring and intelligent production.

Biomass carbon nanosphere-based piezoresistive flexible pressure sensors for motion capture and health monitoring

Biomass carbon-based flexible sensors have shown significant potential in various applications. Indeed, biomass carbon-based flexible sensors, such as carbonized cotton fabrics, exhibit limitations in terms of sensitivity and response speed. Herein, a kind of biomass carbon nanosphere-based flexible pressure sensor was proposed and developed by embedding biomass carbon nanospheres on the skin-hair structures of the polydimethylsiloxane surface. The carbon nanospheres were obtained through the carbonization of cuttlefish ink. Owing to the skin-hair structures fabricated on the surface of the composite films, the sensors achieve a sensitivity of 135.2 kPa−1 in the pressure range of 0–1 kPa. In addition, the sensors exhibit a short response (43 ms) and recovery time (23 ms). With these properties, the sensors can capture and monitor various motions as well as the characteristic waveforms of the wrist pulse, such as the percussion wave (P wave), tidal wave (T wave), and diastolic wave (D wave).

Biobased, degradable and directional porous carboxymethyl chitosan/lignosulfonate sodium aerogel-based piezoresistive pressure sensor with dual-conductive network for human motion detection

The rapid growth of wearable electronics, healthcare monitoring, and human–computer interaction has sparked growing interest in flexible piezoresistive pressure sensors, which in turn raised considerable concerns about the increasingly serious environmental pollution caused by electronic waste. Herein, a radial inward directional freezing-drying method was proposed to prepare biobased, degradable and directional porous carboxymethyl chitosan/lignosulfonate sodium aerogel with dual-conductive network constructed by carboxylated multiwalled carbon nanotubes (C-CNTs) and MXene for piezoresistive pressure sensor. Owing to the synergistic conductive network of C-CNTs and MXene as well as directional porous structure, the sensor exhibited high sensitivity (2.33 kPa−1 in 0–10 kPa, 1.04 kPa−1 in 10–31 kPa, 0.53 kPa−1 in 31–53 kPa), fast response (response/recovery time of 140/60 ms), and excellent repeatability (2,000 loading–unloading cycles). Moreover, the sensor was successfully applied for human motion detection, healthy monitoring, micro-expression identification, and speech recognition. In addition, the aerogel for sensor was able to be completely degraded within 70 h in 1 M hydrochloric acid solution or partially degraded in boiling water within 2.5 h for the recycling of conductive materials, which was beneficial for not only environment protection but also saving resource. Our findings conceivably stand out as a new strategy to prepare environmentally friendly and high-performance piezoresistive pressure sensor and will promote the further development and application of flexible electronics.

Flexible and washable MXene@PEDOT:PSS@CS@PU pressure sensors

Flexible electronics have attracted great interest because of their potential applications in healthcare monitoring and human-computer interaction. The performance of flexible electronics depends on the design of structure, materials, and mechanical responses. In this work, we explore the use of polyurethane (PU) sponge as the scaffold to form flexible piezoresistive pressure sensors with conductive networks made from conductive polymer PEDOT:PSS and MXene nanosheets. The sensitivity of the prepared pressure sensors reaches 0.2171 kPa−1 under mechanical pressure in a range of 1.8–6.15 kPa. The prepared pressure sensors are re-usable after washing. The applications of the prepared pressure sensors in the sensing of physiological behavior are demonstrated under the action of finger tapping, finger bending, vocal cord vibration, swallowing, and pulsing of radial artery. The prepared pressure sensors have great prospects for applications in human-machine interaction and physiological diagnosis.

Flexible Laser-Reduced Graphene with Gradient-Wrinkled Microstructures for Piezoresistive Pressure Sensors

Flexible Laser-Reduced Graphene with Gradient-Wrinkled Microstructures for Piezoresistive Pressure Sensors

Advancing Wearable Cardiovascular Monitoring: Integration of Flexible Piezoresistive Sensors for Robust Pulse Waveform Detection

Wearable, flexible piezoresistive pressure sensors have diverse applications, spanning electronic skin, robotic limbs, and cardiovascular monitoring. Recent advancements in wearable health monitoring devices utilizing these sensors show promise for continuous cardiovascular monitoring. However, a substantial gap exists between laboratory development and market availability for pressure sensor based pulse monitoring. Challenges include the lack of effective testing schemes ensuring robust wearable operation and the necessity of bulky signal acquisition equipment, limiting adaptability. This study addresses these challenges by integrating the outputs of multiple flexible, skin-mountable piezoresistive sensors to create a robust wearable platform. This platform encompasses both sensing and miniaturized signal acquisition for arterial pulse waveform monitoring. The single piezoresistive sensor in our design exhibits sensitivity (1.4 kPa-1 at 2 – 8 kPa). This robust signal allows for the use of simple, compact signal collection devices mounted on a wristband. Moreover, the capability of the the system allows for detection of the three distinct peaks associated with the full pulse waveform, including the systolic, diastolic, and reflected diastolic peaks. In validation, a comparison between the wrist pulse waveform obtained with the compact signal collection device and a standard sourcemeter (Keithley 2460) confirms the capability of our wearable system to resolve the three distinct peaks. This work contributes to bridging the gap between research and practical applications, offering a potential solution for widespread adoption of continuous cardiovascular monitoring technology in diverse settings.