Solvothermal synthesis of zinc oxide: A combined experimental and theoretical study

Zinc oxide is of interest in many applications as an important material with excellent combination of optical, electrical and microstructural properties. In order to optimize the properties of ZnO material for the highly technical or biomedical applications it is necessary to control its structure and morphology. This research is a follow up to our previous investigations [1, 2]. In a previous paper [2] we studied and compared the impact of a versatile family of ethanolamines (MEA and TEA) on the microstructural properties of the ZnO particles prepared in ethanol. In the present work zinc oxide particles were synthesized from zinc acetylacetonate in the presence of triethanolamine (TEA) and various alcoholic solvent, ethanol or octanol, at 170°C. The structural, optical and morphological characteristics of ZnO particles were monitored using X-ray powder diffraction (XRD), UV-Vis spectroscopy and field emission scanning electron microscopy (FE-SEM). The experimental findings are confirmed by means of DFT calculations. On the basis of both microstructural and theoretical studies, the nucleation and growth mechanism of ZnO nanoparticles is proposed. The nucleation and formation mechanism of ZnO nanoparticles was proposed considering the results obtained from a computational study of Gibbs free energies of ZnO−TEA molecular interactions (G*INT) in various solvent system. The calculations revealed different binding affinities which initiated the nucleation processes of ZnO into nanoparticles in the presence of alcohols of different size and polarity. The high chelating efficiency of TEA towards zinc with tetrahedral geometry is observed.