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.