Ultrasensitive self-powered pressure sensing system

doi:10.1016/j.eml.2015.01.008

Extreme Mechanics Letters

Volume 2, March 2015, Pages 28-36

https://doi.org/10.1016/j.eml.2015.01.008 Get rights and content

Abstract

Portable and flexible pressure sensors with highly sensitive and small size have great potential applications in areas such as wearable electronics, environmental monitoring, and medical equipment. Here, we demonstrate an integrated self-powered pressure sensing system made of a passive resistive pressure sensor and a triboelectric nanogenerator. Based on wrinkled and flexible polydimethylsiloxane films, the whole device is of sandwich structure with ultrahigh sensitivity to pressure ( $204.4 {kPa}^{- 1}$ ), which is more than one order of magnitude higher than all previously reported flexible pressure sensors. And our system exhibits a very low detection limit, rapid response time, and long-term stability. In addition, we built a self-powered, portable visualization system for semi-quantitative analysis of pressure, which can directly convert a pressure information to visual display.

Introduction

Highly sensitive, cost-effective, flexible and portable pressure sensors hold an essential position in the development of artificial sensing system. So far, pressure sensors have been reported based on various detection mechanisms, such as resistive [1], [2], [3], [4], [5], [6], [7], [8], [9], capacitive [10], [11], [12], piezoelectric [13], [14], [15], optical [16], [17], and triboelectric [18], [19]. Among these, resistive pressure sensor (resis-sensor) is used more frequently due to its significant advantages of high sensitivity and rapid response. And it has an excellent performance in monitoring continuous pressure. A common drawback of this type of sensors is that a power source is required for their operation. Most recently, the triboelectric nanogenerator (TENG) [20] has been invented as a promising energy harvesting technology and used for self-powered pressure sensing [18], [19]. Even more enticing, TENG operates as a sensor using the electric signal generated by itself without applying an external power source, named as active sensor [21]. This kind of active pressure sensor is very sensitive to the pulse pressure. Moreover, it can be easily assembled into a sensor array for self-powered positioning and imaging [19], [22], [23], [24], [25], although its sensitivity needs to be further improved. With the development of microelectronics and nanotechnology, the power consumption of the resistive pressure sensors gradually reduce, which is beneficial to be powered by energy-harvesting devices [8], such as TENG. Therefore, it might be a feasible way to overcome the shortcomings of these two kinds of pressure sensors through integrating the resis-sensor and TENG into a single device.

In recent years, owing to its simplicity, cost-effectiveness, flexibility, stretchability, and the ability to be patterned in large areas, surface wrinkling on polydimethylsiloxane (PDMS) has received special attention as a key technology for various future applications, such as optical switching devices [26], [27], tunable diffraction gratings [28], [29], [30], tunable microfluidics [31], [32], microcontact printing masters [33], [34], and flexible electronic devices [35], [36]. Additionally, it has been proven that the microstructured PDMS can apparently improve the performance of TENGs and flexible pressure sensors [7], [10], [12], [18]. Despite the superior properties of the wrinkled PDMS, to date, it has not yet been used in designing TENGs and flexible pressure sensors.

Here, based on the wrinkled and flexible structure, we devised an ultrasensitive self-powered pressure sensing system, by innovatively integrated the resis-sensor and TENG into a signal device. The wrinkled PDMS employed in the present work effectively improves the electrical output performance of the TENG and the sensitivity of pressure sensors. The whole sensing system exhibits excellent performances of ultra-high sensitivity, very low detection limit, rapid response time, and long-term stability. Combining a display unit, we further built a portable visualization pressure sensing system, which is able to convert the pressure information to visual display directly. We anticipate that this self-powered sensing system could be expanded to other types of self-powered sensors, such as gas sensor, ion sensor, biosensor, and multifunctional sensing might be realized. This work greatly promotes the development of self-powered system, and lays a solid foundation for establishing the future self-powered sensing network.

Section snippets

Result and discussion

Concept of the self-powered sensing system. The concept of our integrated self-powered sensing system is illustrated in Fig. 1(a). Firstly, the TENG can be used as self-powered active sensors. In the same time, it harvests different kinds of energy from the environment and stores it in the energy storage unit. Then the collected energy is used to drive the other passive sensor. These two kinds of sensors can work simultaneously and complementarily. The magnitude of detection parameters will be

Conclusion

In summary, we have developed a simple, cost-effective method to fabricate an ultrasensitive self-powered pressure sensing system, by innovatively integrating the resis-sensor and the TENG into a single device. With the help of wrinkled and flexible PDMS, our sensing system exhibits multiple excellent performances. The resis-sensor demonstrates ultra-high sensitivity ( $204.37 {kPa}^{- 1}$ ) in the low-pressure regime ( $< 800 Pa$ ), very low detection limit (0.2 Pa), and rapid response time ( $< 0.07 s$ ).

Acknowledgments

This research was supported by the “thousands talents” program for pioneer researcher and his innovation team, China, National Natural Science Foundation of China (Grant No. 51432005), and Beijing City Committee of science and technology project (Z131100006013004, Z131100006013005). The authors would like to thank Weiming Du, Liming Zhang and Chao Yuan for helpful discussions and assistance in experiments.

Conflict of interest

The authors declare no competing financial interest.

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¹: J.L. and F.R.F. contributed equally in this work.

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Ultrasensitive self-powered pressure sensing system

Abstract

Introduction

Section snippets

Result and discussion

Conclusion

Acknowledgments

Nano Energy

Nano Energy

Stretchable carbon nanotube strain sensor for human-motion detection

Nature Nanotechnol.

A flexible and highly sensitive strain-gauge sensor using reversible interlocking of nanofibres

Nature Mater.

An ultra-sensitive resistive pressure sensor based on hollow-sphere microstructure induced elasticity in conducting polymer film

Nature Commun.

A wearable and highly sensitive pressure sensor with ultrathin gold nanowires

Nature Commun.

Giant tunneling piezoresistance of composite elastomers with interlocked microdome arrays for ultrasensitive and multimodal electronic skins

ACS Nano

Microstructured graphene arrays for highly sensitive flexible tactile sensors

Small

Silk-molded flexible, ultrasensitive, and highly stable electronic skin for monitoring human physiological signals

Adv. Mater.

Highly stretchable resistive pressure sensors using a conductive elastomeric composite on a micropyramid array

Adv. Mater.

A flexible and highly pressure-sensitive graphene polyurethane sponge based on fractured microstructure design

Adv. Mater.

Highly sensitive flexible pressure sensors with microstructured rubber dielectric layers

Nature Mater.

Skin-like pressure and strain sensors based on transparent elastic films of carbon nanotubes

Nature Nanotechnol.

Flexible polymer transistors with high pressure sensitivity for application in electronic skin and health monitoring

Nature Commun.

Taxel-addressable matrix of vertical-nanowire piezotronic transistors for active and adaptive tactile imaging

Science

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Macromol. Rapid Commun.

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Adv. Mater.

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