Flexible capacitive pressure sensor based on one-step laser-reduced graphene oxide electrodes and polyurethane/MXene dielectric

Capacitive pressure sensors based on graphene materials and flexible polymers have found extensive applications in electronic skins. However, the fabrication of graphene thin films on polymer substrates is often complex and prone to quality issues. This study proposes a novel one-step laser-reduction method for preparing sensor electrodes, producing laser-reduced graphene oxide (LRGO) electrodes on polyethylene terephthalate (PET) substrates with low sheet resistance and enhanced structural integrity. Additionally, the incorporation of MXene into the polyurethane (PU) dielectric layer increases the dielectric constant and improves the sensor’s relative resistance. The resulting capacitive pressure sensor exhibits a sensitivity of 0.21 kPa⁻¹, significantly higher than the previously reported value of 0.0655 kPa⁻¹ for similar graphene configurations. The sensor demonstrates a response time and recovery time of 400 ms and 500 ms, respectively, and the minimum detectable pressure is 0.05 kPa. Practical applications, including real-time low-pressure response, mouse button press monitoring, finger joint flexion tracking, and grip pressure measurement, highlight the sensor’s potential for electronic skin applications. This study advances the development of high-performance, affordable capacitive pressure sensors by utilizing polymer materials and laser technology.