Large Scale Synthesis of Zinc Oxide Nano- and Submicro-Structures by Pechini's Method: Effect of Ethylene glycol/Citric Acid Mole Ratio on Structural and Optical Properties

Znic oxide nano- and submicro-structures have been synthesized controllably by the polymeric precursor method (Pechini). In this approach, zinc acetate Zn(CH3COO)2.2H2O, citric acid and ethylene glycol were used as the source of Zn2+, the chelating agent and the connecting agent, respectively. The microstructure of the ZnO nano- and submicro-structures was characterized by X-ray diffractometry (XRD) and scanning electron microscopy (SEM) with the energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR). The effect of ethylene glycol to citric acid mole ratio on the morphology and structure of the products was discussed. Different morphologies such as nanoparticles, circular and hexagonal submicro-rods was achieved by changing EG:CA mole ratio. The ZnO nano- and submicro-rods was obtained with EG:CA mole ratio equal to 4:1.The optical property was investigated by the room temperature photoluminescence (PL) spectra. Rod-like and spherical ZnO nanostructures show strong UV emission but hexagonal ZnO submicro-rods show both UV (at ˜ 384 nm) and green emission (at ˜ 510 nm) are observed in the PL spectra.