Laser Thermochemical Synthesis of MXene/Graphene Heterostructure for a Highly Sensitive Flexible Pressure Sensor

Laser-induced graphene (LIG) shows broad application prospects in flexible pressure sensors due to its adjustable electrical properties, good economy, and roll-to-roll compatibility. Incorporating an appropriate nanomaterial into LIG is an effective method to significantly improve its pressure-sensitive properties. In this study, we report an MXene nanoengineered LIG for highly sensitive flexible piezoresistive sensors. The photochemically synthesized MXene-derived nanosheets are anchored in the porous network of LIG to form a MXene/graphene heterostructure (LIMG) by in situ coconversion of MXene/Polyamide acid (PAA) composite under laser irradiation. Benefiting from the conductive paths created by MXene nanosheets in LIG matrix and the stable chemical bonding of MXene-LIG interfaces, the LIMG sensor exhibits a sensitivity of 20 kPa(-1), which is 567% higher than the LIG sensor. Meanwhile, the sensor has a wide range of 80 kPa, fast response/recovery time of 42/28 ms, and excellent stability over 4000 cycles. In practical applications, the LIMG sensor effectively monitors human physiological signals, such as voice, pulse, and respiration, proving its broad prospects in wearable health monitoring. Furthermore, the preparation of two-dimensional/three-dimensional (2D/3D) heterostructures by one-step laser coconversion is expected to promote the development of nanomaterial synthesis technology.