Highly responsive screen-printed asymmetric pressure sensor based on laser-induced graphene

Author(s):  
Jiang Zhao ◽  
Jiahao Gui ◽  
Jinsong Luo ◽  
Jing Gao ◽  
Caidong Zheng ◽  
...  

Abstract Graphene-based pressure sensors have received extensive attention in wearable devices. However, reliable, low-cost, and large-scale preparation of structurally stable graphene electrodes for flexible pressure sensors is still a challenge. Herein, for the first time, laser-induced graphene (LIG) powder are prepared into screen printing ink, and shape-controllable LIG patterned electrodes can be obtained on various substrates using a facile screen printing process, and a novel asymmetric pressure sensor composed of the resulting screen-printed LIG electrodes has been developed. Benefit from the 3D porous structure of LIG, the as-prepared flexible LIG screen-printed asymmetric pressure sensor has super sensing properties with a high sensitivity of 1.86 kPa−1, low detection limit of about 3.4 Pa, short response time, and long cycle durability. Such excellent sensing performances give our flexible asymmetric LIG screen-printed pressure sensor the ability to realize real-time detection of tiny body physiological movements (such as wrist pulse and pronunciation action). Besides, the integrated sensor array has a multi-touch function. This work could stimulate an appropriate approach to designing shape-controllable LIG screen-printed patterned electrodes on various flexible substrates to adapt the specific needs of fulfilling compatibility and modular integration for potential application prospects in wearable electronics.

Polymers ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 3465
Author(s):  
Jianli Cui ◽  
Xueli Nan ◽  
Guirong Shao ◽  
Huixia Sun

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.


Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 664 ◽  
Author(s):  
Junsong Hu ◽  
Junsheng Yu ◽  
Ying Li ◽  
Xiaoqing Liao ◽  
Xingwu Yan ◽  
...  

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.


2014 ◽  
Vol 62 (4) ◽  
pp. 759-763 ◽  
Author(s):  
S. Walczak ◽  
M. Sibiński

Abstract The paper presents a comparative analysis of two types of flexible temperature sensors, made of carbon-based nanostructures composites. These sensors were fabricated by a low-cost screen-printing method, which qualifies them to large scale, portable consumer electronic products. Results of examined measurements show the possibility of application for thick film devices, especially dedicated to wearable electronics, also known as a textronics. Apart from general characterisation, the influence of technological processes on specific sensor parameters were examined, particulary the value of the temperature coefficient of resistance (TCR) and its stability during the device bending.


2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Guanzheng Wu ◽  
Siming Li ◽  
Jiayu Hu ◽  
Manchen Dong ◽  
Ke Dong ◽  
...  

Purpose This paper aims to study the working principle of the capacitive pressure sensor and explore the distribution of pressure acting on the surface of the capacitor. Herein, a kind of high sensitivity capacitive pressure sensor was prepared by overlaying carbon fibers (CFs) on the surfaces of the thermoplastic elastomer (TPE), the TPE with high elasticity is a dielectric elastomer for the sensor and the CFs with excellent electrical conductivity were designed as the conductor. Design/methodology/approach Due to the excellent mechanical properties and electrical conductivity of CFs, it was designed as the conductor layer for the TPE/CFs capacitive pressure sensor via laminating CFs on the surfaces of the columnar TPE. Then, a ‘#' type structure of the capacitive pressure sensor was designed and fabricated. Findings The ‘#' type of capacitive pressure sensor of TPE/CFs composite was obtained in high sensitivity with a gauge factor of 2.77. Furthermore, the change of gauge factor values of the sensor under 10 per cent of applied strains was repeated for 1,000 cycles, indicating its outstanding sensing stability. Moreover, the ‘#' type capacitive pressure sensor of TPE/CFs was consisted of several capacitor arrays via laminating CFs, which could detect the distribution of pressure. Research limitations/implications The TPE/CFs capacitive pressure sensor was easily fabricated with high sensitivity and quick responsiveness, which is desirably applied in wearable electronics, robots, medical devices, etc. Originality/value The outcome of this study will help to fabricate capacitive pressure sensors with high sensitivity and outstanding sensing stability.


Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7385
Author(s):  
Xingjie Su ◽  
Chunli Luo ◽  
Weiguo Yan ◽  
Junyi Jiao ◽  
Dongzhou Zhong

Resistive pressure sensors are appealing due to having several advantages, such as simple reading mechanisms, simple construction, and quick dynamic response. Achieving a constantly changeable microstructure of sensing materials is critical for the flexible pressure sensor and remains a difficulty. Herein, a flexible, tunable resistive pressure sensors is developed via simple, low-cost microsphere self-assembly and graphene/carbon nanotubes (CNTs) solution drop coating. The sensor uses polystyrene (PS) microspheres to construct an interlocked dome microstructure with graphene/CNTs as a conductive filler. The results indicate that the interlocked microdome-type pressure sensor has better sensitivity than the single microdome-type and single planar-type without surface microstructure. The pressure sensor’s sensitivity can be adjusted by varying the diameter of PS microspheres. In addition, the resistance of the sensor is also tunable by adjusting the number of graphene/CNT conductive coating layers. The developed flexible pressure sensor effectively detected human finger bending, demonstrating tremendous potential in human motion monitoring.


Author(s):  
Jing Wang ◽  
Longwei Li ◽  
Lanshuang Zhang ◽  
Panpan Zhang ◽  
Xiong Pu

Abstract Highly sensitive soft sensors play key roles in flexible electronics, which therefore have attracted much attention in recent years. Herein, we report a flexible capacitive pressure sensor with high sensitivity by using engineered micro-patterned porous polydimethylsiloxane (PDMS) dielectric layer through an environmental-friendly fabrication procedure. The porous structure is formed by evaporation of emulsified water droplets during PDMS curing process, while the micro-patterned structure is obtained via molding on sandpaper. Impressively, this structure renders the capacitive sensor with a high sensitivity up to 143.5 MPa-1 at the pressure range of 0.068~150 kPa and excellent anti-fatigue performance over 20,000 cycles. Meanwhile, the sensor can distinguish different motions of the same person or different people doing the same action. Our work illustrates the promising application prospects of this flexible pressure sensor for the security field or human motion monitoring area.


Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3895
Author(s):  
Yelin Ko ◽  
Chi Cuong Vu ◽  
Jooyong Kim

Flexible and wearable pressure sensors have attracted significant attention owing to their roles in healthcare monitoring and human–machine interfaces. In this study, we introduce a wide-range, highly sensitive, stable, reversible, and biocompatible pressure sensor based on a porous Ecoflex with tilted air-gap-structured and carbonized cotton fabric (CCF) electrodes. The knitted structure of electrodes demonstrated the effectiveness of the proposed sensor in enhancing the pressure-sensing performance in comparison to a woven structure due to the inherent properties of naturally generated space. In addition, the presence of tilted air gaps in the porous elastomer provided high deformability, thereby significantly improving the sensor sensitivity compared to other dielectric structures that have no or vertical air gaps. The combination of knitted CCF electrodes and the porous dielectric with tilted air gaps achieved a sensitivity of 24.5 × 10−3 kPa−1 at 100 kPa, along with a wide detection range (1 MPa). It is also noteworthy that this novel method is low-cost, facile, scalable, and ecofriendly. Finally, the proposed sensor integrated into a smart glove detected human motions of grasping water cups, thus demonstrating its potential applications in wearable electronics.


NANO ◽  
2019 ◽  
Vol 14 (07) ◽  
pp. 1950081 ◽  
Author(s):  
Wendan Jia ◽  
Qiang Zhang ◽  
Yongqiang Cheng ◽  
Dong Zhao ◽  
Yan Liu ◽  
...  

Flexible pressure sensors based on piezoresistive induction have recently become a research hotspot due to the simple device structure, low energy consumption, easy readout mechanism and excellent performance. For practical applications, flexible pressure sensors with both high sensitivity and low-cost mass production are highly desirable. Herein, this paper presents a high-sensitivity piezoresistive pressure sensor based on a micro-structured elastic electrode, which is low cost and can be mass-produced by a simple method of sandpaper molding. The micro-structure of the electrode surface under external pressure causes a change in the effective contact area and the distance between the electrodes, which exhibits great pressure sensitivity. The test results show that the surface structure is twice as sensitive as the planar structure under low pressure conditions. This is because of the special morphology of silver nanowires (AgNWs), which exhibits the tip of nanostructures on the surface and realizes the quantum tunneling mechanism. The sensor has high sensitivity for transmitting signals in real time and it can also be used to detect various contact actions. The low cost mass production and high sensitivity of flexible pressure sensors pave the way for electronic skin, wearable healthcare monitors and contact inspection applications.


2011 ◽  
Vol 254 ◽  
pp. 94-98 ◽  
Author(s):  
Li Shiah Lim ◽  
Woo Tae Park ◽  
Liang Lou ◽  
Han Hua Feng ◽  
Pushpapraj Singh

Pressure sensors using MEMS technology have been advanced due to their low cost, small size and high sensitivity, which is an advantage for biomedical applications. In this paper,silicon nanowire was proposed to be used as the piezoresistors due to the high sensitivity [1][2].The sensors were designed, and characterized for the use of medical devices for pressure monitoring. The pressure sensor size is 2mm x 2mm with embedded SiNWs of 90nm x150nm been fabricated. Additionally, the sensitivity of 0.0024 Pa-1 pressure sensor has been demonstrated.


Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 716
Author(s):  
Xiao-Quan Shen ◽  
Ming-Ding Li ◽  
Jun-Peng Ma ◽  
Qun-Dong Shen

Multi-functional electronic skin is of paramount significance for wearable electronics in health monitoring, medical analysis, and human-machine interfacing systems. In order to achieve the function of natural skin, mechanical sensing with high sensitivity is an important feature of electronic skin. Inspired by the spinosum structure under the skin, herein, we fabricate a new capacitive pressure sensor with two-dimensional transition-metal carbides and nitrides (MXene) and ferroelectric polymer (P(VDF-TrFE-CFE)) as an active layer and micropatterned Cr-Au deposited on polydimethylsiloxane as flexible electrodes. Such a method is facile, effective, easily operated, and low-cost. The device design provides great capacitive change as a consequence of large deformation under pressure. Benefiting from the randomly distributed microstructure and high dielectric constant of the active layer, the device demonstrates high sensitivity with great linearity (16.0 kPa−1 for less than 10 kPa), that is, a low detection limit of 8.9 Pa, and quick response. A series of dynamic physiological signals, including typing, knuckle motion, and voice recognition can be facilely detected, making it a competitive candidate in the field of wearable electronics.


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