scholarly journals Improved High-Yield PMMA/Graphene Pressure Sensor and Sealed Gas Effect Analysis

Micromachines ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 786
Author(s):  
Ying Liu ◽  
Yong Zhang ◽  
Xin Lin ◽  
Ke-hong Lv ◽  
Peng Yang ◽  
...  
Keyword(s):  
Pressure Sensor ◽  
Performance Optimization ◽  
High Performance ◽  
Pressure Sensors ◽  
Pressure Change ◽  
Finite Depth ◽  
High Yield ◽  
Through Hole ◽  
Gas Effect ◽  
Pressure Cavity

Graphene with atomic thickness possesses excellent mechanical and electrical properties, which hold great potential for high performance pressure sensing. The exposed electron of graphene is always cross-sensitive to any pollution absorbed or desorbed on the surface, from which the long-term stability of the graphene pressure sensor suffers a lot. This is one of the main obstacles towards graphene commercial applications. In this paper, we utilized polymethylmethacrylate (PMMA)/graphene heterostructure to isolate graphene from the ambient environment and enhance its strength simultaneously. PMMA/graphene pressure sensors, with the finite-depth cavities and the through-hole cavities separately, were made for comparative study. The through-hole device obtained a comparable sensitivity per unit area to the state of the art of the bare graphene pressure sensor, since there were no leaking cracks or defects. Both the sensitivity and stability of the through-hole sensor are better than those of the sensor with 285-nm-deep cavities, which is due to the sealed gas effect in the pressure cavity. A modified piezoresistive model was derived by considering the pressure change of the sealed gas in the pressure cavity. The calculated result of the new model is consistent with the experimental results. Our findings point out a promising route for performance optimization of graphene pressure sensors.

scholarly journals Polymer-Assisted Pressure Sensor with Piezoresistive Suspended Graphene and Its Temperature Characteristics

NANO ◽  
2019 ◽  
Vol 14 (10) ◽  
pp. 1950130 ◽  
Author(s):  
Xin Lin ◽  
Ying Liu ◽  
Yong Zhang ◽  
Peng Yang ◽  
Xianzhe Cheng ◽  
...  
Keyword(s):  
Pressure Sensor ◽  
Pressure Sensors ◽  
Temperature Response ◽  
Pressure Change ◽  
High Yield ◽  
Cavity Pressure ◽  
Suspended Graphene ◽  
Temperature Characteristics ◽  
Sensor Performance ◽  
Sensor Resistance

A polymer-assisted pressure sensor with piezoresistive suspended graphene is proposed and fabricated with high yield. Our sensor exhibits a good pressure response comparable to that of commercial sensors. The sensitivity is estimated to be [Formula: see text][Formula: see text]kPa[Formula: see text], higher than that of similar Si-based pressure sensors. The influence of the temperature on the sensor performance is systematically analyzed. An inverse temperature response is observed, and a nonnegligible temperature effect on the sensor resistance is demonstrated. Considering the temperature-induced cavity pressure change, a new temperature–resistance model is built to explain the nonlinearity of the sensor response to the temperature variation. Experiments under different test voltages show the influence of the current thermal effect, which is similar to that of temperature and nonnegligible for high-precision pressure sensors. Our new sensor holds great potential for practical application, and the findings on the temperature characteristics open up a route to further improve the sensor performance.

scholarly journals Nano Carbon Black-Based High Performance Wearable Pressure Sensors

Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 664 ◽  
Author(s):  
Junsong Hu ◽  
Junsheng Yu ◽  
Ying Li ◽  
Xiaoqing Liao ◽  
Xingwu Yan ◽  
...  
Keyword(s):  
Carbon Black ◽  
Pressure Sensor ◽  
High Performance ◽  
Large Scale ◽  
Pressure Sensors ◽  
High Sensitivity ◽  
Wearable Electronics ◽  
Atmospheric Pollutant ◽  
Piezoresistive Pressure Sensor ◽  
Nano Carbon

The reasonable design pattern of flexible pressure sensors with excellent performance and prominent features including high sensitivity and a relatively wide workable linear range has attracted significant attention owing to their potential application in the advanced wearable electronics and artificial intelligence fields. Herein, nano carbon black from kerosene soot, an atmospheric pollutant generated during the insufficient burning of hydrocarbon fuels, was utilized as the conductive material with a bottom interdigitated textile electrode screen printed using silver paste to construct a piezoresistive pressure sensor with prominent performance. Owing to the distinct loose porous structure, the lumpy surface roughness of the fabric electrodes, and the softness of polydimethylsiloxane, the piezoresistive pressure sensor exhibited superior detection performance, including high sensitivity (31.63 kPa−1 within the range of 0–2 kPa), a relatively large feasible range (0–15 kPa), a low detection limit (2.26 pa), and a rapid response time (15 ms). Thus, these sensors act as outstanding candidates for detecting the human physiological signal and large-scale limb movement, showing their broad range of application prospects in the advanced wearable electronics field.

A flexible pressure sensor based on an MXene–textile network structure

2019 ◽  
Vol 7 (4) ◽  
pp. 1022-1027 ◽  
Author(s):  
Tongkuai Li ◽  
Longlong Chen ◽  
Xiang Yang ◽  
Xin Chen ◽  
Zhihan Zhang ◽  
...  
Keyword(s):  
Network Structure ◽  
Pressure Sensor ◽  
High Performance ◽  
Pressure Sensors ◽  
Wearable Electronics ◽  
Physiological Signal ◽  
Signal Perception ◽  
Performance Pressure ◽  
Human Machine Interfaces ◽  
Flexible Pressure Sensor

High-performance pressure sensors have attracted considerable attention recently due to their promising applications in touch displays, wearable electronics, human–machine interfaces, and real-time physiological signal perception.

scholarly journals Temperature Characteristics of a Pressure Sensor Based on BN/Graphene/BN Heterostructure

Sensors ◽  
2019 ◽  
Vol 19 (10) ◽  
pp. 2223 ◽  
Author(s):  
Mengwei Li ◽  
Teng Zhang ◽  
Pengcheng Wang ◽  
Minghao Li ◽  
Junqiang Wang ◽  
...  
Keyword(s):  
Temperature Coefficient ◽  
Pressure Sensor ◽  
High Performance ◽  
Pressure Sensors ◽  
Resistance Change ◽  
Change Rate ◽  
Influence Of Temperature ◽  
Temperature Characteristics ◽  
Device Resistance ◽  
Influence Of Temperature On

Temperature is a significant factor in the application of graphene-based pressure sensors. The influence of temperature on graphene pressure sensors is twofold: an increase in temperature causes the substrates of graphene pressure sensors to thermally expand, and thus, the graphene membrane is stretched, leading to an increase in the device resistance; an increase in temperature also causes a change in the graphene electrophonon coupling, resulting in a decrease in device resistance. To investigate which effect dominates the influence of temperature on the pressure sensor based on the graphene–boron nitride (BN) heterostructure proposed in our previous work, the temperature characteristics of two BN/graphene/BN heterostructures with and without a microcavity beneath them were analyzed in the temperature range 30–150 °C. Experimental results showed that the resistance of the BN/graphene/BN heterostructure with a microcavity increased with the increase in temperature, and the temperature coefficient was up to 0.25%°C−1, indicating the considerable influence of thermal expansion in such devices. In contrast, with an increase in temperature, the resistance of the BN/graphene/BN heterostructure without a microcavity decreased with a temperature coefficient of −0.16%°C−1. The linearity of the resistance change rate (ΔR/R)–temperature curve of the BN/graphene/BN heterostructure without a microcavity was better than that of the BN/graphene/BN heterostructure with a microcavity. These results indicate that the influence of temperature on the pressure sensors based on BN/graphene/BN heterostructures should be considered, especially for devices with pressure microcavities. BN/graphene/BN heterostructures without microcavities can be used as high-performance temperature sensors.

scholarly journals Flexible and Highly Sensitive Pressure Sensors Based on Microstructured Carbon Nanowalls Electrodes

Nanomaterials ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 496 ◽  
Author(s):  
Xi Zhou ◽  
Yongna Zhang ◽  
Jun Yang ◽  
Jialu Li ◽  
Shi Luo ◽  
...  
Keyword(s):  
Pressure Sensor ◽  
High Performance ◽  
Limit Of Detection ◽  
Pressure Sensors ◽  
High Sensitivity ◽  
Physiological Signals ◽  
Healthcare Applications ◽  
Highly Sensitive ◽  
Carbon Nanowalls ◽  
Pressure Regime

Wearable pressure sensors have attracted widespread attention in recent years because of their great potential in human healthcare applications such as physiological signals monitoring. A desirable pressure sensor should possess the advantages of high sensitivity, a simple manufacturing process, and good stability. Here, we present a highly sensitive, simply fabricated wearable resistive pressure sensor based on three-dimensional microstructured carbon nanowalls (CNWs) embedded in a polydimethylsiloxane (PDMS) substrate. The method of using unpolished silicon wafers as templates provides an easy approach to fabricate the irregular microstructure of CNWs/PDMS electrodes, which plays a significant role in increasing the sensitivity and stability of resistive pressure sensors. The sensitivity of the CNWs/PDMS pressure sensor with irregular microstructures is as high as 6.64 kPa−1 in the low-pressure regime, and remains fairly high (0.15 kPa−1) in the high-pressure regime (~10 kPa). Both the relatively short response time of ~30 ms and good reproducibility over 1000 cycles of pressure loading and unloading tests illustrate the high performance of the proposed device. Our pressure sensor exhibits a superior minimal limit of detection of 0.6 Pa, which shows promising potential in detecting human physiological signals such as heart rate. Moreover, it can be turned into an 8 × 8 pixels array to map spatial pressure distribution and realize array sensing imaging.

scholarly journals Hierarchical network enabled flexible textile pressure sensors with ultra-high sensitivity, ultra-wide linearity and high-temperature resistance

2021 ◽  
Author(s):  
Meiling Jia ◽  
Chenghan Yi ◽  
Yankun Han ◽  
Xin Li ◽  
Guoliang Xu ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Pressure Sensor ◽  
High Performance ◽  
Full Range ◽  
Pressure Sensors ◽  
Fiber Surface ◽  
High Sensitivity ◽  
Harsh Environments ◽  
Point To Point

Abstract Thin, lightweight, and flexible textile pressure sensors with the ability to precisely detect the full range of faint pressure (< 100 Pa), low pressure (in the range of KPa) and high pressure (in the range of MPa) are in significant demand to meet the requirements for applications in daily activities and more meaningfully in some harsh environments, such as high temperature and high pressure. However, it is still a major challenge to fulfill these requirements simultaneously in a single pressure sensor. Herein, a high-performance pressure sensor enabled by polyimide fiber fabric with functionalized carbon-nanotube (PI/FCNT) is obtained via a facile electrophoretic deposition (EPD) approach. High-density FCNT is evenly wrapped and chemically bonded to the fiber surface during the EPD process, forming a conductive hierarchical fiber/FCNT matrix. Benefiting from the abundant yet firm contacting points, point-to-point contacting mode, and high elastic modulus of both PI and CNT, the proposed PI/FCNT pressure sensor exhibits ultra-high sensitivity (3.57 MPa− 1), ultra-wide linearity (3.24 MPa), exceptionally broad sensing range (~ 45 MPa), and long-term stability (> 4000 cycles). Furthermore, under a high working temperature of 200 ºC, the proposed sensor device still shows an ultra-high sensitivity of 2.64 MPa− 1 within a wide linear range of 7.2 MPa, attributing to its intrinsic high-temperature-resistant properties of PI and CNT. Thanks to these merits, the proposed PI/FCNT(EPD) pressure sensor could serve as an E-skin device to monitor the human physiological information, precisely detect tiny and extremely high pressure, and can be integrated into an intelligent mechanical hand to detect the contact force under high-temperature (> 300 ºC), endowing it with high applicability in the fields of real-time health monitoring, intelligent robots, and harsh environments.

scholarly journals High-Sensitivity Flexible Pressure Sensor-Based 3D CNTs Sponge for Human–Computer Interaction

Polymers ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 3465
Author(s):  
Jianli Cui ◽  
Xueli Nan ◽  
Guirong Shao ◽  
Huixia Sun
Keyword(s):  
Pressure Sensor ◽  
High Performance ◽  
Large Scale ◽  
Low Cost ◽  
Pressure Sensors ◽  
Chemical Vapor ◽  
High Sensitivity ◽  
Wearable Electronics ◽  
Wide Range ◽  
Flexible Pressure Sensors

Researchers are showing an increasing interest in high-performance flexible pressure sensors owing to their potential uses in wearable electronics, bionic skin, and human–machine interactions, etc. However, the vast majority of these flexible pressure sensors require extensive nano-architectural design, which both complicates their manufacturing and is time-consuming. Thus, a low-cost technology which can be applied on a large scale is highly desirable for the manufacture of flexible pressure-sensitive materials that have a high sensitivity over a wide range of pressures. This work is based on the use of a three-dimensional elastic porous carbon nanotubes (CNTs) sponge as the conductive layer to fabricate a novel flexible piezoresistive sensor. The synthesis of a CNTs sponge was achieved by chemical vapor deposition, the basic underlying principle governing the sensing behavior of the CNTs sponge-based pressure sensor and was illustrated by employing in situ scanning electron microscopy. The CNTs sponge-based sensor has a quick response time of ~105 ms, a high sensitivity extending across a broad pressure range (less than 10 kPa for 809 kPa−1) and possesses an outstanding permanence over 4,000 cycles. Furthermore, a 16-pixel wireless sensor system was designed and a series of applications have been demonstrated. Its potential applications in the visualizing pressure distribution and an example of human–machine communication were also demonstrated.

Low-cost, highly sensitive and stable pressure sensor based on glass fiber surfacing mat coated with graphene

2019 ◽  
Vol 13 (02) ◽  
pp. 2051002
Author(s):  
Shaowei Lu ◽  
Junchi Ma ◽  
Keming Ma ◽  
Shuai Wang ◽  
Xiangdong Yang ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Glass Fiber ◽  
Pressure Sensor ◽  
High Performance ◽  
Low Cost ◽  
Epoxy Group ◽  
Pressure Sensors ◽  
Superior Performance ◽  
Filtration Method ◽  
Potential Applications

High-performance pressure sensors have caused widespread concern due to the potential applications in 3D-touch technology and wearable electronic devices. Herein, a new type of graphene pressure sensor based on the glass fiber surfacing mat coated with graphene oxide aqueous solution by a spray-vacuum filtration method and HI acid reduction method is reported. It is a simple and highly effective method to reduce graphene oxide films into highly conductive graphene films without destroying their integrity and flexibility at a low temperature based on the nucleophilic substitution reaction. The FTIR, SEM and conductivity tests indicate that the optimum time for graphene oxide to be reduced is 30[Formula: see text]min, under this condition enter the epoxy group has been reacted without damaging the regular sp2 hybrid C atom structure in graphene. The conductivity of the graphene pressure sensor is increased significantly to 23260[Formula: see text]S/m. The monotonic compressing test for 100[Formula: see text]Pa/s and the test of the metal block placement and removal demonstrate that the sensor exhibits relatively high linearity of 99.74% between the response and pressure, the advantage makes the sensor monitor pressure more accurately. More importantly, the pressure sensor based on the glass fiber surfacing mat coated with graphene shows extremely high sensitivity (0.169[Formula: see text][Formula: see text]), fast response time (251[Formula: see text]ms) and good stability for 1000 cycles. Based on its superior performance, it also demonstrates potential applications in measuring pressure and human body’s motions.

scholarly journals A Soft Pressure Sensor Array Based on a Conducting Nanomembrane

Micromachines ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 933
Author(s):  
Daekwang Jung ◽  
Kyumin Kang ◽  
Hyunjin Jung ◽  
Duhwan Seong ◽  
Soojung An ◽  
...  
Keyword(s):  
Pressure Sensor ◽  
High Performance ◽  
Sensor Array ◽  
Pressure Sensors ◽  
Strain Range ◽  
High Sensitivity ◽  
Critical Issue ◽  
Mechanical Stimuli ◽  
Highly Sensitive ◽  
Accumulated Strain

Although skin-like pressure sensors exhibit high sensitivity with a high performance over a wide area, they have limitations owing to the critical issue of being linear only in a narrow strain range. Various strategies have been proposed to improve the performance of soft pressure sensors, but such a nonlinearity issue still exists and the sensors are only effective within a very narrow strain range. Herein, we fabricated a highly sensitive multi-channel pressure sensor array by using a simple thermal evaporation process of conducting nanomembranes onto a stretchable substrate. A rigid-island structure capable of dissipating accumulated strain energy induced by external mechanical stimuli was adopted for the sensor. The performance of the sensor was precisely controlled by optimizing the thickness of the stretchable substrate and the number of serpentines of an Au membrane. The fabricated sensor exhibited a sensitivity of 0.675 kPa−1 in the broad pressure range of 2.3–50 kPa with linearity (~0.990), and good stability (>300 Cycles). Finally, we successfully demonstrated a mapping of pressure distribution.

Performance Optimization of a Capacitive Pressure Sensor

2015 ◽  
Vol 644 ◽  
pp. 101-105 ◽  
Author(s):  
F. Kerrour ◽  
M. Salah Kemouche ◽  
Aziz Beddiaf
Keyword(s):  
Performance Optimization ◽  
High Performance ◽  
Biomedical Application ◽  
Pressure Sensors ◽  
Complete Analysis ◽  
Capacitive Pressure Sensor ◽  
Sensor Structure ◽  
Cavity Thickness ◽  
Silicon Based ◽  
The Impact

In this paper, the thermo-mechanical modelling of an entire sensor structure, under hydrostatic pressure, is carried out using commercial FEM software COMSOL multiphysics. A comparison of the obtained results with those found in the literature, allows us to corroborate the well-known models. Furthermore, the design of high performance conventional silicon-based pressure sensors for low-pressure biomedical applications has been achieved by optimizing the influencing parameters on the two features mentioned above.For a specific biomedical application, a complete analysis, considering the impact of the device thickness, embedding type and diaphragm material, has shown that the highest performances are reached for a silicon diaphragm thickness of 65μm, a circular shape having a radius of 1750μm and a cavity thickness of 4.6μm. Simulation results show that the sensor under investigation yields a quasi linear response with pressure values lying in the range [0 ÷70kPa]. The pressure sensitivity is about 2 pF/bar, and the thermal drift is about 16 ppm/°C for a temperature range [-20°C÷ 150°C]. The obtained results may well contribute to the optimization of the device’s performances and can provide to the designer several chosen criteria for a given application.

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