All-Carbon Piezoresistive Sensor: Enhanced Sensitivity and Wide Linear Range via Multiscale Design for Wearable Applications

Piezoresistive sensors are indispensable in applications such as healthcare monitoring, artificial intelligence, and advanced communication systems. However, achieving wearable sensors that offer both high sensitivity and a wide linear range remains a significant challenge. Here, an all-carbon piezoresistive sensor is presented, named, featuring high biocompatibility, chemical stability, environmental sustainability, and a straightforward fabrication process. This sensor, integrating a double-sided pyramidal carbon aerogel (DPA) as the sensing layer, a silicone frame as the elastic support (ES), and superhydrophobic graphene-coated nylon fabric as the breathable conductive substrate (BCS), was named as DPA-ES@BCS. Finite element analysis confirms that the synergistic interaction between the DPA and silicone frame enhances the sensor's sensitivity while extending its linear range. This multiscale design achieves an exceptional sensitivity of 37.3 kPa-1, a broad linear detection ranges from 0 to 1.4 MPa, and outstanding stability over 30 000 cycles. Additionally, the high-performance wearable sensor is well-suited for real-time physiological signal monitoring and demonstrates exceptional capability in voice recognition, accurately distinguishing words using machine learning algorithms. Moreover, the DPA-ES@BCS sensor array shows great potential for enhancing information security through dual-factor authentication. This approach not only advances the piezoresistive performance of all-carbon sensors but also provides a strong foundation for developing next-generation sensor technologies.