Enhancing the output performance of ZnO nanosheet based piezoelectric nanogenerator by molar ratio modifications

Abstract

The current work shows how the molar ratio of zinc nitrate and hexamethylenetetramine (HMTA) affects the output performance of a ZnO nanosheet-based piezoelectric nanogenerator. ZnO nanosheets were synthesized at three different molar concentrations of HMTA with fixed zinc nitrate hexahydrate concentration (1:1, 1:2, and 1:3). The shape, crystallinity, chemical composition, and photoluminescence properties of ZnO nanosheet films were further studied. The increased concentration of HMTA in solution results in larger and thinner nanosheets. In addition, three piezoelectric nanogenerators were fabricated using these ZnO nanosheet films deposited on two sides of an aluminum foil. The larger ZnO nanosheet film-based nanogenerator (PENG3) produced an enhanced output voltage than the smaller ZnO nanosheet film-based nanogenerator (PENG1) with an average output voltage of ∼423 mV and an average short-circuit current of ∼0.697 µA, respectively. The output voltage of PENG3 was enhanced by 1.55 times and short-circuit current by 1.34 times compared to the PENG1 device. PENG3 has an instantaneous output power of about 0.2277 mW/m2 at a load resistance of 250 kΩ. The photoluminescence study also confirmed that this could be used as a suitable UV light sensor. In addition, these highly porous nanosheets can also be used for photovoltaic materials in DSSC applications.