Performance of flexible ZnO nanowire piezoelectric generators enhanced by bifacial superposition

High performance piezoelectric nanogenerators have important applications in many fields. In this work, we report a bifacial superposed zinc oxide piezoelectric nanogenerator that shows better performance than a single unit. A stainless steel substrate with both front and back zinc oxide nanowire arrays is an elementary unit. Then we engage in an alternating superposition of two elementary units with a carbon-contained polyurethane foil. Multiple units can be similarly assembled by adding alternating structures to further enhance the piezoelectric output performance. Nanogenerators obtained by the above bifacial method are flexible and stability with high output. The method can be used to increase the overall piezoelectric performance and is expected to have a wide application in self-powered device fields.