Vol. 8, Special Issue 4 (2023)

Author(s): Somveer, F Magdaline Eljeeva Emerald, Kumari M and Shivananda

Abstract: Ensuring the optimum storage conditions for nanoparticles (NPs) is crucial for their successful utilization and shelf-life determination. In this research, freshly synthesized zinc oxide (ZnO) NPs were subjected to a 6-months storage study under air-tight conditions at room temperature and pressure to investigate the effects of storage period and conditions on their properties. UV-visible spectroscopy was employed to characterize the ZnO NPs for changes in purity, stability, agglomeration, and optical properties. A maximum absorption peak at 381 nm in the UV-visible spectra confirmed the presence of ZnO NPs. Absence of major peaks in the range of 300-450 nm affirmed the purity of ZnO NPs, indicating the absence of impurities. A red-shift in the UV-visible spectra indicated agglomeration of NPs over the storage period. A significant 29.8% reduction in the energy band gap value was observed in stored ZnO NPs compared to freshly synthesized ones (3.25 eV). This reduction in the energy band gap value inferences an increase in the size due to the agglomeration of NPs during storage.