Confined Laser-Induced Dual Graphene Films for Multifunctional Sensors

Laser-induced graphene (LIG) offers a versatile platform for high-performance sensors owing to its porous structure, good conductivity, and chemical tunability. However, the application of LIG in next-generation sensors is limited by its insufficient substrate compatibility and sensing functionality. To address these challenges, we propose a confined laser-induced dual graphene (CLDG) approach that leverages laser photothermal and shockwave effects to simultaneously fabricate graphene films on both flexible and rigid substrates. In this approach, polyimide powder confined between a thermoplastic elastomer (TPE) substrate and a glass substrate is carbonized by an infrared laser to form two face-to-face graphene films on these two substrate surfaces. The TPE-based graphene film is used to achieve a flexible piezoresistive sensor with an ultrahigh sensitivity of 400 kPa–1 at 0–5 kPa. The application of the sensor in dynamic load testing, speech recognition, and gesture detection demonstrates its promising prospects. Meanwhile, based on the glass-based graphene film, a temperature sensor with a high sensitivity of −0.359% °C–1 is prepared and used for real-time detection of water temperature. These results indicate that the proposed CLDG method provides a scalable and efficient route for fabricating multifunctional sensors, advancing the practical application of laser-induced graphene technology in electronic systems.