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Hydrothermal Growth of One-Dimensional and Two Dimensional ZnO Nanostructures and Their Properties.

Record Type:	Language materials, manuscript : Monograph/item
Title/Author:	Hydrothermal Growth of One-Dimensional and Two Dimensional ZnO Nanostructures and Their Properties./
Author:	Sakurai, Shota.
Description:	1 online resource (86 pages)
Notes:	Source: Dissertations Abstracts International, Volume: 85-04, Section: B.
Contained By:	Dissertations Abstracts International85-04B.
Subject:	Nanotechnology. -
Online resource:	click for full text (PQDT)
ISBN:	9798380605342

Hydrothermal Growth of One-Dimensional and Two Dimensional ZnO Nanostructures and Their Properties.
Sakurai, Shota.

Hydrothermal Growth of One-Dimensional and Two Dimensional ZnO Nanostructures and Their Properties. - 1 online resource (86 pages)

Source: Dissertations Abstracts International, Volume: 85-04, Section: B.

Thesis (Ph.D.)--State University of New York at Binghamton, 2023.

Includes bibliographical references

Zinc oxide (ZnO) nanomaterials have attracted great attention from researchers over the decades. ZnO nanostructured materials can be synthesized in easy, environmental-friendly ways at low cost. ZnO is a Ⅱ-Ⅵ semiconductor compound and is well known to show high photocatalytic and antibacterial activities. When ZnO is in the nanoscale, it obtains some advantages over its bulk since ZnO nanomaterials have a high surface-to-volume ratio and different physiochemical properties, which makes their photocatalytic and antibacterial properties greatly improved. Also, even among those ZnO nanomaterials, one-dimensional (1D) and two-dimensional (2D) nanomaterials are expected to show different properties since the dominant surface of 1D ZnO nanomaterials is a non-polar plane, m-plane, while that of 2D is a polar plane, c-plane. To be 2D, ZnO must grow along its a- or m-axis, while suppressing the growth along its c-axis, which is preferable in ZnO growth due to the reactive, polar c-plane. In this study, 2D ZnO was hydrothermally grown by epitaxial growth templated by an r-plane-oriented aluminum oxide (Al2O3) seed layer and by the transformation of 2D hydrozincite into ZnO on a ZnO seed layer. From scanning electron microscopy (SEM) observation, hexagonal-shaped 2D ZnO nanoplates seemed to be grown only on the r-plane Al2O3 seed crystals, which made an incomplete coverage of the seed layer with ZnO nanoplates. On the other hand, 2D ZnO nanostructures transformed from hydrozincite were found to fully cover the ZnO seed layer with a plenty of mesoporous 2D ZnO flake-like nanostructures. From transmission electron microscopy (TEM) analysis of the transformed mesoporous 2D ZnO nanoflakes from hydrozincite, it was confirmed that the majority surface of those consisted of the m-plane. However, largely exposed c-plane was the mesopores formed by the transition. The photocatalytic property was evaluated with methylene blue dye solution under UV light and visible light irradiation. The antibacterial activity was assessed using a carrier test under UV light, visible light, and dark environment with the Gram-positive bacterium, Staphylococcus aureus (S. aureus), and the Gram-negative bacterium, Pseudomonas aeruginosa (P. aeruginosa) and an attachment assay with S. aureus expressing green fluorescence protein (GFP). In both tests at all conditions, 2D ZnO showed better performance than 1D ZnO and ZnO thin film. Photoluminescence analysis revealed that 2D ZnO surfaces were more defective having dominant zinc interstitial and oxygen vacancy defects, which could contribute to both photocatalytic and antibacterial performance. The bandgap energy of 2D ZnO was determined to be 3.19 eV using the Tauc plot analyzing UV-Vis spectroscopy data. The effective bandgap energy narrowing (\uD802\uDD03Eg = 0.18 eV) was observed due to the dominant zinc interstitial defects, which create a shallow defect level beneath the conduction band of ZnO. High concentration of oxygen vacancy defect creating the defect energy level above the valance band could also contribute to the bandgap narrowing. Effective bandgap narrowing could improve the photocatalytic and antimicrobial activities under visible light. This study shows that 2D ZnO nanomaterials are very promising as a photocatalyst and an antimicrobial substance.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2024

Mode of access: World Wide Web

ISBN: 9798380605342Subjects--Topical Terms:

557660
Nanotechnology.
Subjects--Index Terms:

Antibacterial activitiesIndex Terms--Genre/Form:

554714
Electronic books.

Hydrothermal Growth of One-Dimensional and Two Dimensional ZnO Nanostructures and Their Properties.
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