High-power energy harvesting and imperceptible pulse sensing through peapod-inspired hierarchically designed piezoelectric nanofibers

High-performance energy harvesting for human-sensing applications has been achieved through recent progress in piezoelectric-based wearable devices. Piezoelectric nanomaterials can be leveraged for flexibility and biocompatibility while also enhancing piezoelectricity. However, such nanomaterials exhibit low piezoelectricity, limits the industrial-scale development of highly efficient piezoelectric devices. Hence, design of novel materials to significantly enhance piezoelectricity is necessitated. Herein, we demonstrate that a peapod-inspired design in which ZnSnO₃ anchored on surface-modified carbon nanotubes (CNT) allows significant enhancement of the piezoelectricity produced by poly(vinylidene fluoride-co-trifluoroethylene)-based (P(VDF-TrFE)-based) nanofibers (a piezoelectric material). The piezoelectric properties were exploited for the application of the as-prepared nanofibers (NFs) in flexible NFs in energy-harvesting and pulse-sensing systems, which demonstrated high output power ((97.5 V and 1.16 μA) as well as imperceptible pulse detection even in posterior tibial arteries. This work provides the scientific and engineering framework for delivering ZnSnO₃-surface-modified CNT-P(VDF-TrFE) NFs excellent piezoelectric performance for use in piezoelectric devices.