Biogenic SiO2-induced β-phase engineering in electrospun PVDF nanofibers for self-powered, sub-millisecond impact sensing.

Flexible piezoelectric materials capable of resolving transient mechanical events are essential for emerging sensing systems. In this work, electrospun PVDF nanofibers incorporating biogenic SiO2 nanoparticles derived from rice husk were developed to investigate the relationship between structural evolution and dynamic electromechanical response. Structural analyses confirmed that SiO2 incorporation promotes β-phase formation, increasing its fraction from 53.03% to 69.71%. The fabricated device exhibited stable output under periodic excitation (5, 8, and 11 Hz), with an average peak voltage of 659.04 ± 14 mV, corresponding to an ∼13.6% enhancement compared to pristine PVDF. Under dynamic impact conditions (1.7-13.7 mJ), the device generated well-defined voltage transients with a strong linear dependence on impact energy (R2 = 0.958). Time-resolved analysis revealed a rapid electromechanical response, with a rise time of 0.46 ms, a peak-to-peak interval of 0.14 ms, and a recovery time of ∼1 ms. These results indicate efficient stress-to-charge conversion and fast signal stabilization within the nanofibrous architecture. The combined effects of enhanced electroactive phase content, low inertial mass, and effective stress transfer enable reliable time-resolved sensing, highlighting the potential of the PVDF-SiO2 system for self-powered detection of dynamic mechanical stimuli.