Hydrothermally synthesized KNN NPs boosting P(VDF-TrFE) piezoelectricity for energy harvesting and physiological monitoring

The development of wearable technology has been driven by the increasing demand for flexible and sensitive sensors that can utilize body motion to generate electricity or acquire physiological data for health assessment and rehabilitation. In this work, piezoelectric materials K 0.5 Na 0.5 NbO 3 nanoparticles (KNN NPs), synthesized through a one-step hydrothermal method, were integrated into poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] films to enhance their electrical properties for application in wearable piezoelectric nanogenerator (PENG) sensors. The maximum content of β phase in the composite film is as high as 83.1%, which may be attributed to the enhancement of polar interface interactions. The PENG sensors exhibited an open-circuit voltage of 12 V, a short-circuit current of 0.86 μA, and a peak power of 3.18 μW under optimal load, showcasing superior performance and stability over 4700 cycles. Monitoring results from human body motion demonstrated the potential application prospects of PENG sensors in motion analysis and medical rehabilitation.