Effect of synthesis parameters on the optical, structural and morphological properties of wet-synthesized zinc oxide (ZnO) nanostructures

In this research Zinc Nitrate Hexahydrate [Formula: see text] was used to synthesize Zinc oxide (ZnO) nanostructures and polyethylene glycol ([Formula: see text] was used as the capping agent. During the synthesis process temperature and concentration of ammonium hydroxide [Formula: see text] and [Formula: see text] were changed to control the size and morphology of the synthesized ZnO nanostructures. The structural and physical investigations of synthesized ZnO nanostructures were done using UV–Vis spectrophotometry, scanning electron microscopy (SEM) equipped with energy dispersive X-ray analysis (EDXA) and X-ray powder diffraction (XRD). The XRD analysis indicated an enhancement in crystallite size from 16.14[Formula: see text]nm to 17.98[Formula: see text]nm, which further increased to 43.39[Formula: see text]nm as the concentration of [Formula: see text] was varied from 5[Formula: see text]mL to 15[Formula: see text]mL (at the rate of increment of 5[Formula: see text]mL each time). While the crystallite decreases from 17.98[Formula: see text]nm to 4.75[Formula: see text]nm as the concentration of [Formula: see text] increases from 0.5[Formula: see text]g to 1.5[Formula: see text]g (at the rate of increment of [Formula: see text] 0.5[Formula: see text]g in each step). The maximum crystallite size of 47.15[Formula: see text]nm was observed in ZnO.7 at room temperature and decreased with increment of temperature. Optical absorption spectra showed that ZnO.5 has a maximum direct bandgap of 3.68[Formula: see text]eV at [Formula: see text]C with the concentration of [Formula: see text] and [Formula: see text] of 10[Formula: see text]mL and 1.5[Formula: see text]g respectively. Overall, the study demonstrated that the size, morphology and optical properties of ZnO nanostructures can be effectively controlled by varying temperature, the concentration [Formula: see text] and [Formula: see text] during the synthesis process. The results could have significant implications for the development of ZnO-based nanoelectronics devices and other applications.