Synthesis and Characterization of Flower‐Like Bundles of ZnO Nanosheets by a Surfactant‐Free Hydrothermal Process

Abstract

Flower-like bundles of ZnO nanosheets have been prepared by using preheating hydrothermal process without any surfactants. The flower-like bundles consist of many thin and uniform hexagonal-structured ZnO nanosheets, with a thickness of 50 nm. The selected area electronic diffraction (SAED) and high-resolution transmission electron microscope (HRTEM) images indicate that the ZnO nanosheets are single crystal in nature. The growth mechanism of the flower-like bundles of ZnO nanosheets is discussed based on the morphology evolution with growth times and reaction conditions. It is believed that the formation of flower-like bundles of ZnO nanosheets is related to the shielding effect of OH−ions and the self-assembly process, which is dominated by a preheating time. Room temperature photoluminescence spectra results show that the annealing atmosphere strongly affects the visible emission band, which is sensitive to intrinsic and surface defects, especially oxygen interstitials, in flower-like bundles of ZnO nanosheets.

Interactions of Zinc Oxide Nanostructures with Mammalian Cells: Cytotoxicity and Photocatalytic Toxicity

“…The synthesis takes place in an autoclave acting as the reaction vessel for thermal treatment. Increasing solution temperature accelerates the reactions between zinc salt precursor, solvent and capping agent as expected [81,[96][97][98][99][100]. In comparison to conventional heating in hydrothermal and solvothermal processes, microwave heating offers several advantages including rapid heating, high reaction rate, and increased production yield [101][102][103][104][105][106].…”

The effect of growing time and Mn concentration on the defect structure of ZnO nanocrystals: X-ray diffraction, infrared and EPR spectroscopy

“…The pH of the solution, which is important for the nanopowder formation, was adjusted to 10 by addition of (NH 3 ). 35,36 The resulting solution was kept in Teon-lined autoclave at 70 C for various duration times such as 1 h, 6 h, 12 h, 24 h and 36 h. Aer cooling down to RT, the precipitate was ltered, washed with distilled water several times, and dried in an oven at 80 C for 1 h. The ZnO nanopowders are probably occurred by the following formation subsequent mechanisms: The Mn-doped ZnO nanopowder was also synthesized with the same technique. The Mn(NO 3 ) 2 $4H 2 O solution was added into the solution of which is used to prepare ZnO nanopowder (6 h).…”

Green synthesis of ZnO nanoparticles by Aspalathus linearis: Structural & optical properties

“…A rich variety of physical (vapor-phase process) and chemical (solution phase) methodologies were used to synthesize undoped or doped ZnO [6]. The vapor-phase process includes molecular beam epitaxy [7], metal-organic chemical vapor deposition [8], sputtering method [9], pulsed laser deposition [10], infrared irradiation [11], thermal decomposition [12],and thermal evaporation and condensation [13] which are favored for the high quality of the ZnO final product.…”