Vertical graphene on flexible substrate, overcoming limits of crack-based resistive strain sensors

Hong Ryeol Na,Seung-Hyun Chun,Sanjib Baran Roy,Sunghun Lee,Yong Ju Yun,Jae Ho Jeon,Sahng-Kyoon Jerng,Han-Jin Kim,Hyun Joo Lee

doi:10.1038/s41528-022-00135-1

Hong Ryeol Na, Seung-Hyun Chun + Show 7 more

Open Access

https://doi.org/10.1038/s41528-022-00135-1

Copy DOI

Abstract

Resistive strain sensors (RSS) with ultrasensitivity have attracted much attention as multifunctional sensors. However, since most ultrasensitive RSS are designed by cracked conductive metals, the sensing performance is severely degraded due to accumulated structural deformation with consecutive cycles. To overcome such limitation, newly designed structures have been suggested, but the development of mechanosensors exhibiting superior stability and ultrasensitivity still remains a challenge. Here, we demonstrate that vertical graphene (VG) RSS with high sensitivity (gauge factor greater than 5000), remarkable durability (>10,000 cycles), and extraordinary resilience can serve multifunctional applications. We find that well-defined cracks on tufted network structure result in highly reversible resistance variation, especially revivable status even after broken current path, confirmed by microscopic in situ monitoring. The VG integrated with a wireless sensing system exhibits excellent timbre recognition performance. Our findings provide inspirable insights for mechanosensing system, making VG a promising component for future practicable flexible sensor technologies.

Highlights

From simple sensors to the Internet of Things (IoT), strain sensors have garnered attention for a myriad of fields, such as wearable devices, electronic skins, and human-machine interactive devices due to their high sensitivity and/or stretchability[1,2,3,4,5,6,7,8,9,10]
Diverse dimensional nanomaterials like nanotubes and nanoparticles have recently embedded in a strain sensor system[18,19,20,21]
We synthesized vertical graphene (VG) on a SiO2/Si wafer by using the plasmaenhanced chemical vapor deposition (PECVD) method (I in Fig. 1a and Supplementary Note 1)

Summary

Introduction

From simple sensors to the Internet of Things (IoT), strain sensors have garnered attention for a myriad of fields, such as wearable devices, electronic skins, and human-machine interactive devices due to their high sensitivity and/or stretchability[1,2,3,4,5,6,7,8,9,10]. A single resistive strain sensor (RSS) device usually combines the conductive metal and flexible substrate for outstanding electrical and mechanical properties[3,11,13,14]. Released, the resistance was restored to the same level before the VGS was stretched, i.e., no hysteresis was observed, indicating completely reversible behavior under strain and the reliability of c the strain sensors[5].

Results

Conclusion