Optical and structural characteristics of ZnO nanopowders for different preparation methods

Abstract

Zinc oxide (ZnO) nanoparticles (NPs) were synthesized by different methods known as Pechini and Sol-Gel. It was observed during the experiments significant differences comparing these methods as: particle size, time applied, crystallinity and chemical residues generated by-products. The NPs were analysed by X-ray diffraction (XRD), ultraviolet-visible (UV-Vis.) absorption and Raman spectroscopy techniques. X-Ray Difractograms showed peaks corresponding to hexagonal wurtzite crystalline structure. It was observed that NPs obtained by the Pechini showed better homogeneity and crystallinity; these presented average size of 115 nm. The NPs produced by Sol-Gel method showed crystallites with smaller average size of 8 nm. The band gap energy (Eg) obtained using UV-Vis for ZnO NPs synthesized by Pechini was 3.39 eV. Still, the results for Sol-Gel method with 5 and 10 hours of reactions were 3.53 eV and 3.55 eV respectively. Raman data obtained by Pechini and Sol-Gel Methods showed characteristics peaks. The obtained data confirmed the ZnO phase samples and the proportional relationship to the enlargement with the intensity of peaks E 2 High ˜ 438 cm -1 , as evidenced by literature. These results lead to the applicability of both NPs in optoelectronic and fluorescent applications.

The characterization of ZnO nanoparticles by applying x-ray diffraction and different methods of peak profile analysis

“…The chemical methods used for synthesizing nanoparticles are of specific interest, since they have flexible processing chemistry and offer the potential of facile scale. Among these chemical methods, the sol-gel method is attractive because of its low cost, easy controllability and low manufacturing temperature [41][42][43][44]. Citric acid (weak triprotic acid), which is widely available and cheap, is an effective chelating agent: it is one of the most common minor organic molecules used in the sol-gel technique.…”