Stretchable strain sensor based on HfSe₂/LIG composite with high sensitivity and good linearity within a wide range

Abstract

Flexible strain sensors based on nanomaterials have sparked a lot of interest in the field of wearable smart electronics. Laser induced graphene (LIG) based sensors in particular stand out due to their straightforward fabrication procedure, three-dimensional porous structures, and exceptional electromechanical capabilities. Recent studies have focused on LIG composites, however, it is still difficult to achieve great sensitivity and excellent linearity in a wide linear working range. Herein, a strain sensor with high sensitivity and good linearity is prepared in this work, which was realized by carbonizing the polyimide film coated with HfSe₂ to obtain three-dimensional porous graphene nanosheets decorated with HfSe₂ (HfSe₂/LIG). After being transferred to the flexible substrate of Ecoflex, it exhibits high stretchability, hydrophobicity and robustness, and obtains excellent electromechanical properties. The HfSe₂/LIG strain sensor demonstrated high sensitivity (gauge factor, GF ≈ 46), a low detection limit (0.02%), good linearity (R² = 0.99) in a large working range (up to 30%), and a quick response time (0.20 s). Additionally, it exhibits good stability and consistent behavior across a large number of strain/release test cycles (>3000 cycles). With these benefits, the sensor can be used to monitor various limb movements (including finger, wrist and neck movements) and minute artery activity, and can generate reliable signals. Therefore, the HfSe₂/LIG-based sensor has enormous potential for use in wearable intelligent electronics and movement monitoring.