Detecting intermediate particles in the growth of colloidal zinc oxide nanoparticles in different chemical routes using MCR–ALS

Abstract

Zinc oxide (ZnO) nanoparticles have been used in a wide‐ranging of applications such as transparent UV protection, light emitting diodes, sensors and photovoltaic cells. Many applications of ZnO nanoparticles could be improved by changing the particle size, shape and morphology. Therefore, studying the mechanism of shape evolution is crucial for size and shape controlled synthesis of nanocrystaline ZnO particles. As an alternative to sophisticated techniques such as transmission electron microscopy (TEM) and X‐ray powder diffraction (XRD), commonly used for studying nanoparticles evolution, we herein employed UV/Vis spectroscopy for monitoring the evolution process of the ZnO nanocrystals coupled with chemometric methods for analyzing overlapped and complex spectral data. The evolutionary UV‐Visible absorbance data of ZnO nanoparticles through particle formation via precipitation methods in various solution conditions were analyzed using factor analysis, evolving factor analysis, and multivariate curve resolution‐alternative least‐squares analysis. Depending on chemical routs, three or four chemical factors that attributed to the ZnO nanoparticles of different size were detected and the concentration profiles and pure spectra of the particles were resolved. The interpretation of the evolution profiles of the detected ZnO nanoparticles were achieved by Ostwald ripening mechanism. Copyright © 2013 John Wiley & Sons, Ltd.