Enhanced Energy harvesting, utilizing ZnO nanosheet based nanogenerator embedded in phononic crystal

In this report, we present a direct current piezoelectric nanogenerator based on ZnO nanosheets, which is driven by ultrasound waves propagating in water. ZnO nanosheets have been grown by hydrothermal method on Al layer as the bottom ohmic contact, while Ni layer serves as the top Schottky contact. Then, we have designed a 1D phononic crystal to realize localized standing wave at the position of nanogenerator, and consequently enhance the energy harvesting performance. The proposed phononic crystal consists of water/steel periodic slabs which are enclosing both sides of the nanogenerator, and the created mid-gap state is matched with the source frequency in the designed structure. Our simulation results confirm that the pressure difference exerted to the nanogenerator is enhanced by a factor of about 12.3, in comparison with the pristine ZnO nanogenerator.