Synergistic Resistance Modulation toward Ultrahighly Sensitive Piezoresistive Pressure Sensors

Abstract

In recent years, with the rapid development of prosthesis, [1,2] health monitoring, [3][4][5][6][7] and robot, [8][9][10] electronic skin has drawn huge research enthusiasm. Tactile sensation is one of the most significant functions of electronic skin, which mainly relies on pressure sensor to realize. [11][12][13][14][15] Among the different kinds of pressure sensors, piezoresistive pressure sensor demonstrates great application potential because of its fast response speed, simple structure, economical fabrication process and great stability. [16][17][18][19][20] Improvement of sensitivity of pressure sensors is critical for the high precision and ultrasensitive pressure detection, [21][22][23][24][25] which is however a challenging task because the key effect of device configuration on the sensitivity is always neglected.Until now, the commonly used strategy to improve sensitivity focuses on the development of different kinds of microstructure of active materials, but this strategy is still not effective enough to achieve ultrahigh sensitivity. [26][27][28] For example, Fang et al. replicated the lotus leaf surface onto the polydimethylsiloxane (PDMS) substrate to produce a structured layer and then sprayed graphene films as active electrodes, [29] which yields a sensitivity of 1.2 kPa −1 . Jong-jin Park et al. reported a sensor with sensitivity of 10.32 kPa −1 by introducing a pyramidical electrode consisting of a conductive polymer (PEDOT:PSS) and an aqueous polyurethane dispersion (PUD) elastomer blend. [30] Bao et al. prepared a new piezoresistive sensor with sensitivity up to 41.9 kPa −1 by preparing interconnected polypyrrole (PPY) hollow sphere structure through a multiphase synthesis technique. [31] These researches have significantly advanced the development of piezoresistive sensors, but still could not achieve ultrahigh sensitivity to meet the requirement of high precision and ultrasensitive detection. This is because the surface microstructure of active materials is not the only key factor for the improvement of sensitivity.To overcome the current obstacle and get ultrathigh sensitivity, it would be necessary to understand the basic working principle of piezoresistive pressure sensor, and further get the feasible solution. The basic electrical characteristics of piezoresistive sensor is similar, and the total resistance (R total ) of the device consists of two parts: the body resistance (R b ) Improvement of sensitivity of electrical piezoresistive sensors is critical for high-precision and ultrasensitive detection, which mainly depends on the modulation ability of total resistance of sensor under applied pressure. However, in most of the reported sensor devices, the contact resistance and body resistance (the key parts of total resistance of sensor) generally cannot be modulated simultaneously, which results in the limited sensitivity. In this work, an ultrahighly sensitive piezoresistive pressure sensor with an exquisitely designed structure is demonstrated, providing an uncomparable advantage of ...

Flexible and sensitive piezoresistive electronic skin based on TOCN/PPy hydrogel films

“…The design of the internal microstructure of the piezoresistive sensor has greater impact on the sensing performance. Generally, designing the internal microstructure into hollow spheres, 17 pyramids, 18 and multilayers 16 and other structures can improve the sensing performance. Piezoresistive sensors generally consist of substrate and active material.…”

Magnetically induced micropillar arrays for an ultrasensitive flexible sensor with a wireless recharging system

“…This ultrahigh initial resistance could improve sensitivity and reduce power consumption in a standby mode. This balanced combination of the ultrahigh sensitivity and wide linear working range outperforms previously developed sensors [11,[27][28][29][30][31][32][33][34][35][36][37], as illustrated in Fig. 3b.…”

Highly Sensitive, Stretchable Pressure Sensor Using Blue Laser Annealed CNTs

“…However, polymer-composite-film-based piezoresistive pressure sensors typically have the disadvantage of low sensitivity. Therefore, pressure sensors with porous structure [17,34], microstructure [13,[35][36][37], and pyramid structure [38][39][40][41] have been developed to achieve improved sensitivity and response time. The microstructure efficiently modulates the contact resistance and improves the response and recovery speed and the stability of the pressure sensor.…”