Carbonization fabrication of a piezoresistive sensor with improved sensitivity via Ni decoration of carbonized cotton fibers

The development of wearable electronics urgently requires the cost-effective and scalable fabrication of high-performance pressure sensors. This work aims to develop a simple carbonization strategy to facilitate sensor sensitivity by decorating discrete nickel nanoparticles on carbonized cotton fibers (CCFs). The increased air gap between the fibers at the unloading state, as well as the enlargement of the deformation distance and the contact area between the conductive materials at the loading state, contribute to a more significant resistance change. Therefore, the sensitivity of the piezoresistive sensor is improved more than 5 times within 1 N by introducing Ni nanoparticles, and it is characterized by a rapid response (∼160 ms) and recovery (∼100 ms), wide detection range (∼20 N/∼130 kPa), and good durability (∼4000 cycles). The flexible sensor has been successfully demonstrated to monitor human movements, physical stimuli, and pressure distribution. Furthermore, the proposed device can control temperature accurately as a uniform and large-scale heater. This work reveals that the Ni@CCFs-based sensor is prospective in wearable electronics, artificial intelligence, health monitoring, medical diagnosis and treatment.