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

Dapeng Wei,Xi Zhou,Jialu Li,Shi Luo,Jun Yang,Yongna Zhang

doi:10.3390/nano9040496

Abstract

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.

Highlights

Wearable electronics [1,2,3,4,5] and artificial electronic skins [6,7,8] have been developing rapidly
A simple way of fabricating microstructure was introduced, which is illustrated in Figure 1a, where rough silicon wafer with irregular morphology provided a three-dimensional surface for Carbon nanowalls (CNWs) growing
Because the adhesion between CNWs and PDMS is stronger than that between CNWs and silicon, CNWs could be transferred onto PDMS and the composite could act as a flexible electrode

Summary

Introduction

Wearable electronics [1,2,3,4,5] and artificial electronic skins [6,7,8] have been developing rapidly. Bao [21] and co-authors fabricated a pressure sensor with a regular micro-pyramid and micro-hair structure whose sensitivity was quite low (0.58 kPa−1). Ren [22] and his co-authors transferred the structure of abrasive paper to polydimethylsiloxane and fabricated a piezoresistive pressure sensor. There are some disadvantages using the natural templates for the plant leaves are limited by seasonal factors These methods have difficulties in implementing large area array sensing. The development of fabricating materials with various morphologies and microstructures contributes greatly to the advanced pressure sensors. CNWs can be grown in a patterned array on a silicon wafer using a mask These merits make CNWs a promising material in the field of flexible pressure sensors

Methods

Results

Conclusion