Enhanced electromechanical conversion via in situ grown CsPbBr3 nanoparticles/poly(vinylidene fluoride) fibers for physiological signal monitoring

Mechanical energy conversion based on piezoelectric principle has received much attention due to its promising applications in sustainable power supply systems and sensor technology. Ferroelectric poly(vinylidene fluoride) (PVDF) combines the advantages of both good electromechanical coupling and easy processability, yet the low piezoelectric coefficient limits its output performances thus cannot meet the increasing requirements for power generation and sensing. Here, inorganic metal halide perovskite CsPbBr3 (CPB) nanoparticles have been incorporated into the PVDF fibers via electrospinning technique, where an in situ crystallization and growth process of CPB nanoparticles have been established. Meanwhile, both the CPB nanoparticles and PVDF fibers are poled by the electric field during electrospinning process, which promotes the formation of polar phase of PVDF and the distortion of CPB lattice, resulting in greatly enhanced piezoelectric performances of CPB/PVDF composites. The output performances under external force of the flexible generator developed from electrospun CPB/PVDF films are significantly enhanced compared with neat PVDF film, with the maximum Voc value 8.4 times higher; while the measurements on the microscopic piezoelectric responses unambiguously reveal that the increased polar phase mainly contributes to the enhanced electromechanical coupling. The functions of CPB/PVDF film as physiological signals monitoring sensor have been performed, demonstrating its potential applications as flexible piezoelectric generator and wearable health monitoring electronics.