Simultaneously enhancing sensitivity and operation range of flexible pressure sensor by constructing a magnetic-guided microstructure in laser-induced graphene composite

Abstract

Flexible pressure sensors play an essential role in the development of flexible electronic systems, which have been widely used in recent times for human activity monitoring and personal healthcare. However, possessing both high sensitivity and a wide operation range for pressure sensor remains challenging, as these requirements are commonly incompatible with each other. Herein, a magnetic induced graphene composite-based pressure sensor (MIPS) is demonstrated by integrating laser induced graphene (LIG) with a patterned valley-peak microstructure and a graphene film doped with magnetic microspheres. Owing to the synergistic effect of the 3D valley-peak microstructures and intercalation-like microstructures within the LIG composite film, the MIPS demonstrates excellent sensing performance in both sensitivity and operation range. The conductive network formed by graphene flakes improves electromechanical response capability, while the incorporation of magnetic microspheres (MMs) promotes the proliferation of conductive pathways in a small applied pressure range, and the valley-peak structure further enhances compressive strength over a large operation range. Accordingly, the MIPS exhibit excellent sensing capability over a range of 0–830 kPa, with an exceptionally high sensitivity of 4426.12 kPa−1 and excellent mechanical stability and durability (2000 cycles at a pressure of 800 kPa). Additionally, we have developed a novel pressure mapping system utilizing the MIPS array, enabling real-time monitoring of pressure spatial distribution and intensity. Notably, the MIPS array exhibits remarkable potential in diverse applications, including the monitoring of human physiological signals and movement. This pressure sensor with a hierarchically composite microstructure presents a promising candidate for the rapid advancement of next-generation wearable bioelectronics.