Design of a piezoelectric energy harvesting device based on ZnO–Na2Ti6O13 heterojunction nanogenerator

Abstract

Enhancing the performance of nanogenerators is vital in the development of new piezoelectric applications that reveal high sensitivity to the surrounding waste of mechanical vibrational energy. In this paper, two major solutions are presented. The first is an easy and low-cost nanogenerator method utilizing Disodium Hexatitanate (Na2Ti6O13) as an alkali catalyzed material for growing the ZnO seed layer. The second solution is to suppress the screening effect that takes place in ZnO-metal harvester by forming a ZnO–Na2Ti6O13 heterojunction harvester. In other words, improvement can be realized by adopting a p-n junction approach instead of using the traditional Schottky contact approach. The ZnO–Na2Ti6O13 nanogenerator was grown hydrothermally. The size and nanofiber’s shape, material compounds distribution in the p-n junction and the crystal phases are investigated. The result was a fabricated ZnO nanofiber with a length and diameter of 3.726 μm and 0.158 μm respectively and the average crystal size of the Na2Ti6O13 nanofiber was 97.74 nm, with a fiber diameter of approximately 8.699 nm. The maximum AC voltage (Vpk-pk) and current upon finger pressing reached about 2 V and 2 μAcm−2 respectively. A good rectification property resulted based on the use of a p-n junction approach. The ZnO–NTO nanofiber could provide DC voltage up to 3.6 V where the derived energy is sufficient to power LCD digital screen.