Starch-stabilized synthesis of ZnO nanopowders at low temperature and optical properties study

Zinc oxide nanoparticles (ZnO–NPs) were synthesized via the sol–gel method in starch media. Starch was used as a stabilizer to control of the mobility of zinc cations and then control growth of the ZnO–NPs. Because of the special structure of the starch, it permits termination of the particle growth. Thermogravimetry analysis (TGA) was applied on dried gel to obtain the certain calcination temperature(s) of the ZnO–NPs. The dried gel was calcined at different temperatures of 400, 500, and 600 °C. Several techniques such as X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FTIR), and high-magnification transmission electron microscopy (TEM) were used to characterize the ZnO–NPs. The ZnO–NPs calcined at different temperatures exhibited a hexagonal (wurtzite) structure with sizes from 30 to 50 nm. The optical properties of the prepared samples were investigated using UV–vis spectroscopy. The results showed that starch is a suitable stabilizer in the sol–gel technique, and this method is a reasonable and facile method to prepare ZnO–NPs for large-scale production.