Synthesis and Characterization of ZnO Nanostructures Grown via a Novel Atmospheric Pressure Solution Evaporation Method

In this study, a novel method called “atmospheric pressure solution evaporation (APSE)” was developed for growing of Zinc Oxide (ZnO) nanostructures on Al2O3 surface. Zinc acetate dihydrate, Polyvinyl Pyrrolidone, and deionized water were used as precursor, capping, and solvent, respectively. The growth of ZnO nanostructures from evaporated solution was performed at three temperatures of 300, 400, and 500°C. Field emission scanning electron microscopy (FESEM) demonstrated that ZnO nanostructures formed in nanorods or cauliflower-like rods based on the growth temperature. X-ray diffraction patterns of ZnO nanostructures prepared at different growth temperatures were indexed as hexagonal Wurtzite structure without any impurity. The optical band gap energy evaluated by diffuse reflectance spectroscopy (DRS) was 3.22∼3.29 eV. Optical properties of the ZnO nanostructures are investigated by UV–Vis spectroscopy. There is a blue shift in the band edge with changing of the growth temperature. The degradation of Methylene Blue (MB) dye demonstrated that ZnO nanorods grown at the growth temperature of 300°C showed better photodegradation compared to other nanostructures. Antifungal properties of ZnO nanorods against Candida albicans were much higher than that of the other nanostructures. This method, compared to other synthesis methods of ZnO nanostructures, offers several advantages, such as simplicity, cost-effectiveness, low temperature, atmospheric pressure, and large area deposition. Such a low-temperature growth method may expose great opportunities for synthesis of ZnO nanorods onto various low-temperature endurance substrates and extend the field of ZnO-based nanoscale devices.