Impact of Annealing Temperature on Structural, Optical, and Morphological Properties of ZnO Nanoparticles Synthesized by a Simple Precipitation Method

Objective: Herein, we report zinc oxide (ZnO) nanoparticles (NPs) synthesized by a simple precipitation method using zinc acetate dihydrate (Zn(CH3CO2)2. 2H2O) and sodium hydroxide (NaOH) precursors in aqueous media. Methods: Synthesized material was annealed at different temperatures to check phase formation and its purity. Results: At room temperature, the sample shows the formation of zinc hydroxide and at high temperature (100, 200, and 300°C) shows the formation of ZnO. Synthesized materials were analyzed by different techniques. X-ray diffraction analysis shows the formation of a hexagonal crystal structure. Morphological features were analyzed by the SEM technique which shows agglomerated nanoparticles. Conclusion: The optical properties of ZnO were studied by using UV analysis and showed intrinsic excitonic transition property of the ZnO semiconductor. Further, with an increase in annealing temperature crystalline size, agglomeration of nanoparticles found to be increased whereas the bandgap decreased.