Theoretical modeling of a 2D nano-energy harvester

Nano-piezoelectric energy harvesters, due to their ability to convert mechanical vibrations to electrical current, are apt candidates for self-powered NEMs devices. Further, these are strain based electrical potential generators and can be used in tactile devices for accurate position sensing. ZnO, due to its piezoelectric properties and semiconducting nature is the ideal candidate for such applications. This paper proposes an analytical model to explain the potentials generated due to ZnO nano-films on being subjected to different forms of static loading. The model also incorporates the effect of different boundary conditions imposed on the nano-film. A perturbation theory based approach has been used to generate the analytical model. Initially, the strains are calculated ignoring the piezoelectric effect. Later, the electromechanical coupling is taken into consideration and the potentials have been calculated as a second order effect. The finite element simulation results agree with the theory to an accuracy of 5%. The profiles for piezoelectric potential distribution agree also well with the simulations. These piezoelectric potential profiles can also be used in smart materials for obtaining the required deformation in a specimen by applying a similar electrical potential across it.