Self-powered wearable electronics to convert mechanical and thermal energy into electrical energy are important for biomedical monitoring, which highly require good flexibility, comfortability, signal sensitivity, and accuracy. In this work, composite nanofiber mats of polyacrylonitrile (PAN) and trimethylamine borane (TMAB) were prepared by electrospinning, which exhibited excellent piezoelectric and pyroelectric abilities in harvesting mechanical and thermal energy. The PAN/TMAB-4 nanofiber mats not only generated a high voltage of up to 2.56 V and a high power of 0.19 μW upon shape deformation but also exhibited linear voltage response to thermal gradient. The hybrid piezoelectric and pyroelectric output signals were successfully integrated together and have been applied to precisely monitor human vital signs, including elbow bending angles, foot posture, and breathing status, in real time by attaching the flexible sensors to proper human body parts. Overall, good flexibility, bifunctional sensing ability, and self-power make PAN-/TMAB-type sensors very attractive in fabricating high-performance electronics for detecting motion, monitoring health, and making portable microelectronics.
Keywords: PAN/TMAB nanofiber; full flexibility; hybrid nanogenerator; piezoelectric and pyroelectric performance; self-powered sensor.