Enhanced piezoelectric potential of ZnO-based composite piezoelectric nanogenerators with various nanostructures

The development of efficient and flexible piezoelectric nanogenerators (PNGs) is crucial for powering next-generation wearable and self-powered electronic devices. Among various piezoelectric materials, zinc oxide (ZnO) has garnered significant attention for its eco-friendliness, low cost, and facile synthesis into various nanostructures. However, the correlation between different ZnO morphologies and the piezoelectric performance of composite PNGs has not been fully clarified. In this study, we systematically investigate the effects of ZnO nanostructures, including nanoflowers, nanoplates, and nanowires, on the piezoelectric output of ZnO/PDMS composite PNGs through a combined experimental and theoretical approach. To identify the theoretical principles, we developed a multiphysics simulation considering the mechanical and electrical coupling mechanism. Concurrently, ZnO nanostructures were synthesized, and the reaction conditions were precisely controlled to produce distinct morphologies for reliable comparison. The piezoelectric performance of the composite PNGs was systematically evaluated, revealing a strong dependence on the ZnO morphology. Notably, PNGs incorporating ZnO nanoflowers exhibited a significantly enhanced piezoelectric output compared to those with other nanostructures under repetitive mechanical force. The simulation results, which align well with our experimental findings, demonstrate that the unique hierarchical and multi-faceted structure of the nanoflowers is highly advantageous for promoting large-scale deformation. This complex morphology facilitates more efficient and continuous stress transfer from the polymer matrix to the piezoelectric filler, thereby maximizing piezoelectric potential generation. These findings underscore that morphological engineering, particularly the fabrication of nanoflower structures, is a highly effective strategy for advancing the performance of ZnO-based flexible energy harvesting devices.

Min Gyeong Kang is a PhD student specializing in piezoelectric composites. She holds a Master’s degree in Carbon Convergence Materials Engineering from Jeonbuk National University. She has published research on piezoelectric composites and insulating thermal management composites. She is currently conducting research at Jeonbuk National University on enhancing the performance of composite-based piezoelectric nanogenerators.