Ultrahigh Sensitive Flexible Piezoresistive Sensor with Carbonized Metal–Organic Framework Fe<sub>3</sub>O<sub>4</sub>@MIL-100(Fe)
Xi Wu, Jun Yuan, Xuanqi Guo, Lijun Ma, Guoqiang Wu, Gary J. Cheng, Yong Liu, Feng Liu
Abstract
The piezoresistive sensor is an important device for sensing pressure and strain in flexible electronics. The application of composite conductive nanomaterials is helpful to obtain high-performance and multifunctional flexible piezoresistive sensors. Herein, using carbonized Fe3O4@MIL-100(Fe) as a composite conductive nanomaterial, an ultrahigh-sensitivity flexible piezoresistive sensor was achieved by a laser-processed template. Due to the porous Fe3O4@MIL-100(Fe) conductive nanomaterials and microridges on the styrene–isoprene–styrene substrate, the sensitivity of the sensor reaches 1727.46 kPa–1 in the pressure range of 0–50 Pa, which has a significant advantage over the reported sensors. Meanwhile, the sensor exhibits good cycling stability (>1500 cycles), a fast response of 24 ms, an instant recovery of 15 ms, excellent reversibility, and an antielectromagnetic interference capability. For practical applications, the sensor was applied for monitoring body physiological signals such as speech and artery pulses, indicating that the sensor is suitable for health monitoring. Moreover, using carbonized metal–organic frameworks with functional nanoparticles as conductive nanomaterials in the sensing unit provides a feasible way to develop multifunctional flexible piezoresistive sensors.