Graphene/MXene/Cellulose cellulosic paper-based flexible bifunctional sensors utilizing molecular bridge strategy with tunable piezoresistive effect for Temperature-Pressure sensing

Abstract

Wearable technology is changing the way we interact with the digital world. Wearable systems can enable a smarter lifestyle when connected to other smart devices. This work reports a bifunctional sensor prepared from cellulosic paper as substrate for response to both temperature and pressure. The introduction of CMC-Na improves the dispersion of the binary hybrid conductive fillers in the deionized water. Meanwhile, relying on the intermolecular forces of both hydrogen bonding and cation-π interaction, the interfacial interactions of the binary hybrid conductive fillers are strengthened, which is anticipated to create a stable and homogenous conductive layer. And the concept of “effective conductive fillers distribution density” is introduced to explain and analyze the pressure sensing mechanism. The reported sensor has a pressure sensitivity of −1.6189 %/kPa, a sensing range of 370 kPa, and a response recovery time of 37.5 ms/37.5 ms. In addition to its response to mechanical force, the sensor has a detecting range of 23–58 °C, a response recovery time of 325 ms/1000 ms, and a temperature coefficient of resistance (TCR) of −1.77 %/°C. The potential applications of this sensor demonstrate the excellent gesture tracking characteristics, multi-point tactile sensing capability, and dual stimulus–response of the sensor.