Self-powered wearable pressure sensing system for continuous healthcare monitoring enabled by flexible thin-film thermoelectric generator

Flexible and portable pressure sensors with highly sensitive and cost-effective attributes are of great demand in wearable electronics, biomedical monitoring, and artificial intelligence. To realize portable pressure sensors with mobile operation, ultrathin, flexible, and sustainable power sources are highly desired. Here, a self-powered wearable pressure sensing system is developed by integrating a conductive elastomer-based pressure sensor with a flexible thin-film thermoelectric generator (tf-TEG) to harvest body heat. Laser engraving technique is adopted to achieve pressure sensor with tunable sensitivity through the controllable design of surface microstructures. To produce a reliable and renewable power supply for the pressure sensor, the flexible tf-TEG is constructed with high thermal-conductivity insulation films for heat absorbing and flexible hydrogels as heat sink, resulting in a large temperature gradient for high power generation. In particular, the pressure sensitivity of the self-powered system is independent of the temperature gradient across the tf-TEG, allowing it to maintain a stable performance under various temperature differences between human skin and surroundings. For the first time, the self-powered pressure sensing system proposed in this work enables continuous monitoring of human physiological signals and body motions entirely powered by the skin-attachable tf-TEG without an electronic boost circuitry.