Flexible Piezoelectric Sensor Based on P( <scp>VDF</scp> ‐ <scp>TrFE</scp> )/ <scp> BiCl ₃ </scp> / <scp>GR</scp> Fabricated via High‐Voltage Electrospinning for Physiological Signal Monitoring

ABSTRACT To address the challenges of wearing discomfort and poor wearability associated with traditional rigid physiological signal sensors, this study innovatively designed and fabricated a ternary composite flexible piezoelectric thin‐film sensor based on P(VDF‐TrFE)/BiCl 3 /GR. Experimental results demonstrate that the composite film achieves optimal piezoelectric performance with a BiCl 3 doping concentration of 2% and graphene content of 0.1%, exhibiting a rapid response time of 3 ms and a sensitivity of 1.09 V/N. The comparative analysis revealed that the optimized composite film exhibited significantly enhanced performance, with an open‐circuit voltage of 35.82 V and a short‐circuit current of 22.89 μA, corresponding to 4.55 times and 4.59 times improvements over the pure P(VDF‐TrFE) film, respectively. A flexible sensor was subsequently constructed through sandwich‐structured PDMS encapsulation. After signal conditioning involving charge amplification, voltage amplification, and filtering, the sensor successfully captured diverse physiological signals including heart sound signal, arterial pulse signal, and respiratory signal. The proposed flexible piezoelectric sensor demonstrates exceptional performance in physiological signal acquisition, offering a novel strategy for advancing wearable smart health monitoring technologies.