Electrohydrodynamically Printed, Flexible Energy Harvester Using In Situ Poled Piezoelectric Nanofibers

This article presents the fabrication of electrohydrodynamically printed energy harvesters based on piezoelectric polyvinylidene fluoride (PVDF) nanofibers. PVDF nanofibers with phase formation are fabricated by mechano-electrospinning to realize insitu electric poling and mechanical stretching. By directly depositing the poled nanofibers onto flexible or prestrained elastomeric substrates, bendable or stretchable energy harvesters with high efficiency were fabricated. The flexible energy harvesters generate electricity under bending, stretching, and compression, and the generated current is characterized by a linear ratio to the stretching frequency/strain as well as the number of fibers. Additionally, the vertical pressure enables the stretchable energy harvesters with in-surface buckled fibers to generate electricity stably even if the harvesters exist in different stretching statuses. The printed energy harvesters pave the way for a cost-effective, high-efficiency manufacturing pathway in wearable, bio-integrated electronics with large deformability.