Nanostructured CeO2 Thin Films Prepared by the Sol-Gel Dip-Coating Method with Anomalous Behavior of Crystallite Size and Bandgap. (31st October 2019)

• Record Type: Journal Article
• Authors: Acosta-Silva, Y. J.; Toledano-Ayala, M.; Torres-Delgado, G.; Torres-Pacheco, I.; Méndez-López, A.; Castanedo-Pérez, R.; Zelaya-Ángel, O.
• Other Names: Perales-Pérez Oscar Academic Editor.
• Is Part Of: Journal of nanomaterials. Volume 2019(2019)
• Publication Date: 2019-10-31
• Subjects: Nanostructured materials -- Periodicals; Nanotechnology -- Periodicals; Nanomatériaux; Nanostructured materials; Nanotechnology; Nanostructures; Nanotechnology; Periodicals; Fulltext; Internet Resources; Periodicals; 620.115
• DOI: 10.1155/2019/5413134
• Languages: English
• ISSNs: 1687-4110

Abstract

Abstract : Amorphous CeO2 thin films were deposited by a dip-coating method on Corning glass substrates and annealed for one hour at the temperatures (T ) of 250, 450, and 550°C in air for crystallization. The precursor solution was prepared by dissolving cerium acetate in methanol, lactic acid, glycerol, and trimethylamine at 55°C. X-ray diffraction (XRD) patterns showed the cubic structure of CeO2 . From XRD data and employing the Scherrer formula, the crystallite size (CS) was calculated to be within the 4.0 ± 0.5 to 10 ± 1 n m interval. SEM micrographs revealed cracks of the films annealed at 250 and 450°C, even though for 550°C, the film shows a homogeneous morphology free of cracks. CS increases (from 4.0 to 10 nm) and thickness decreases (from 217 to 182 nm) when T increases. The UV-vis spectra exhibited an average transmittance of 80% in the 300 to 2000 nm wavelength range. Also, from XRD, it was observed that the lattice shrinks and from transmittance that the bandgap energy increases with T . The Raman spectra exhibit 461 cm -1 assigned to F2g mode of the fluorite cubic structure, where F2g hardens when T increases as an effect of the shrinkage of the lattice.