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.