Design and manufacturing of zno nanowire and nanowall structures for energy harvesting via flexible piezoelectric and hybrid nanogenerators in wearable textiles

The increasing demand for wearable technologies has highlighted the need for portable and sustainable energy sources. In this context, piezoelectric and triboelectric nanogenerators stand out due to their ability to convert ambient mechanical energy into electrical energy. Their potential to harvest energy from human body movements enables these devices to serve as sustainable power sources within the ecosystem of wearables. However, the performance of nanogenerators is influenced by factors such as module design, the structure of the active layer, and the electrode-active layer interface. In this thesis, ZnO nanowires and nanowalls synthesized via hydrothermal methods, were systematically investigated within the framework of the synthesis–structure relationship. ZnO nanowall structures providing homogeneous growth, reproducibility, and high electrical output were identified as the main focus of the study. The effects of 0.5–2 at. % doping on the ZnO nanowall structure and, consequently, on piezoelectric performance were evaluated according to structure–property–performance relationships. Furthermore, the crucial roles of module architecture, electrode-active layer interface, and contact type (Schottky/Ohmic) on electrical performance were demonstrated through different module designs. In hybrid nanogenerator designs, the contribution of the triboelectric effect enabled high power generation under low forces, successfully powering an LCD screen. The developed modules were also integrated into a glove, confirming their ability to harvest energy from hand movements. Overall, this study, covering the entire process from synthesis to application, demonstrates the feasibility of ZnO nanowall-based flexible nanogenerators in wearable electronics and presents significant potential for commercialization in the field of energy harvesting.