Characterization of hybrid piezoelectric nanogenerators through asymptotic homogenization

In the framework of energy scavenging for applications in flexible/stretchable electronics, hybrid piezoelectric nanogenerators are investigated. They are made up with zinc oxide (ZnO) nanorods, embedded in a polymeric matrix, and grown on a flexible polymeric support. The ZnO nanorods are arranged in clusters, forming nearly regular distributions, so that periodic topologies can be realistically assumed. Focus is on a dynamic multi-field asymptotic homogenization approach, proposed to grasp the overall constitutive behaviour of such complex microstructures. A set of applications, both in static and dynamic regime, is proposed to explore different design paradigms, related to nanogenerators based on three working principles. Both extension and bending nanogenerators are, indeed, analysed, considering either extension along the nanorods axis, or orthogonally to it. The study of the wave propagation is, also, exploited to comprehend the main features of such piezoelectric devices in the dynamic regime.