Bubble-Decorated Honeycomb-Like Graphene Film as Ultrahigh Sensitivity Pressure Sensors

• Published in: Advanced functional materials Vol. 25; no. 41; pp. 6545 - 6551
• Main Authors: Sheng, Lizhi, Liang, Yuan, Jiang, Lili, Wang, Qian, Wei, Tong, Qu, Liangti, Fan, Zhuangjun
• Format: Journal Article
• Language: English
• Published: Blackwell Publishing Ltd 01-11-2015
• Subjects: Contact; Density; Electric potential; Graphene; Pressure sensors; Strain; strain sensors; Switching; Voltage; wearable monitor
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.201502960

Recently, macroporous graphene monoliths (MGMs), with ultralow density and good electrical conductivity, have been considered as excellent pressure sensors due to their excellent elasticity with a rapid rate of recovery. However, MGMs can only exhibit good sensitivity when the strain is higher than 20%, which is undesirable for touch‐type pressure sensors, such as artificial skin. Here, an innovative method for the fabrication of freestanding flexible graphene film with bubbles decorated on honeycomb‐like network is demonstrated. Due to the switching effect depended on “point‐to‐point” and “point‐to‐face” contact modes, the graphene pressure sensor has an ultrahigh sensitivity of 161.6 kPa−1 at a strain less than 4%, several hundred times higher than most previously reported pressure sensors. Moreover, the graphene pressure sensor can monitor human motions such as finger bending and pulse with a very low operating voltage of 10 mV, which is sufficiently low to allow for powering by energy‐harvesting devices, such as triboelectric generators. Therefore, the high sensitivity, low operating voltage, long cycling life, and large‐scale fabrication of the pressure sensors make it a promising candidate for manufacturing low‐cost artificial skin.
A flexible, bubble‐decorated, honeycomb‐like graphene film (BHGF) is fabricated by a low‐temperature heat treatment of graphene oxide film. The as‐prepared BHGF exhibits an ultrahigh sensitivity of 161.6 kPa−1 at a strain less than 4%, due to the switching effect depended on “point‐to‐point” and “point‐to‐face” contact modes.