Environmentally Sustainable Synthesis of Zinc Oxide Nanostructures via Modified Sol-Gel Method for Enhanced Piezoelectric Energy Harvesting Applications

Environmentally Sustainable Synthesis of Zinc Oxide Nanostructures via Modified Sol-Gel Method for Enhanced Piezoelectric Energy Harvesting Applications

The high significance of piezoelectric materials has been highlighted recently due to the growing need for sustainable energy harvesting applications. Zinc Oxide among all the particles is of notable interest because it exhibits excellent piezoelectric prop¬erties along the [001] crystallographic direction. Perhaps, there lies a dilemma of having synthesizing methods that are both envi-ronmentally friendly and affordable with production of high-quality nanostructures with compatible piezoelectric performance. In addressing these challenges, this study fabricated ZnO nanoparticles using a modified sol-gel method while being environmentally sustainable and cost effective. Unlike existing methods that often rely on complex and costly processes or hazardous chemicals, this approach leverages a simplified technique focused on precise substrate preparation to promote the vertical growth of nanorods. We thoroughly characterized the synthesized nanostructures using a suite of analytical techniques. X-ray diffraction (XRD) confirmed a high degree of crystallinity, with a predominant peak corresponding to the c-axis orientation, which is crucial for piezoelectric performance. Scanning electron microscopy (SEM) images revealed the successful formation of vertically aligned nanorods with diameters of approximately 1μm, a morphology essential for effective charge separation and output. Energy-dispersive spectrosco¬py (EDS) analysis further validated the high purity of the synthesized material, confirming the absence of unwanted impurities. With this ZnO nanostructure, a piezoelectric nanogenerator (PENG) was fabricated and its performance was evaluated under mechanical stress. The device demonstrated a remarkable peak output voltage of up to 0.75 V, a significant improvement over values typically reported for similar nanostructures. This result demonstrates the practical efficacy of our synthesis method and device design in enhancing the efficiency of energy harvesting. The findings lay a strong foundation for future advancements in piezoelectric devices for applications in wearable electronics, biomedical sensors, and other smart technologies.