Cover Image

Computational prosess design, optimization and growth of zinc oxide nanostructures on graphene by ultrasonic spray pyrolysis

Computational process design, optimization, growth, characterization and computational analysis of zinc oxide (ZnO) nanostructures grown on graphene using zinc acetylacetonate (Zn(acac)2) in the presence of hydrogen by ultrasonic spray pyrolysis were performed systematically. The dissociation of Zn...

Full description

Saved in:
Bibliographic Details
Main Author: Ali Ibrahim, Amgad Ahmed
Format: Thesis
Language:English
Published: 2016
Subjects:
T58.5-58.64 Information technology
Online Access:http://eprints.utm.my/id/eprint/92559/1/AmgadAhmedAliPMJIIT2016.pdf
http://eprints.utm.my/id/eprint/92559/
http://dms.library.utm.my:8080/vital/access/manager/Repository/vital:106406
Tags: Add Tag
No Tags, Be the first to tag this record!
id my.utm.92559
record_format eprints
spelling my.utm.925592021-09-30T15:11:36Z http://eprints.utm.my/id/eprint/92559/ Computational prosess design, optimization and growth of zinc oxide nanostructures on graphene by ultrasonic spray pyrolysis Ali Ibrahim, Amgad Ahmed T58.5-58.64 Information technology Computational process design, optimization, growth, characterization and computational analysis of zinc oxide (ZnO) nanostructures grown on graphene using zinc acetylacetonate (Zn(acac)2) in the presence of hydrogen by ultrasonic spray pyrolysis were performed systematically. The dissociation of Zn ions from vapour-phase Zn(acac)2 and its adsorption onto graphene oxide were studied using quantum mechanics approach involving the use of Density Functional Theory (DFT). The reaction energies were calculated, and the proposed reaction mechanism was well supported by a simulation of infrared properties. Next, Response Surface Methodology (RSM) was used to model and optimize the pyrolysis parameters by evaluating the nanostructure density, size and shape factor. The evolution of ZnO structures was well explained confirming that RSM is a reliable tool for the modelling and optimization of the pyrolysis parameters and prediction of nanostructure sizes and shapes. Finally, a computational analysis of the measured optical and charge transport properties of the grown nanostructures, i.e. Nanosphere Clusters (NSCs), Nanorods (NRs) and Nanowires (NWs) were developed. The calculated absorbance spectra based on the time-dependent DFT showed very close similarity with the measured behaviours. The atomic models and energy level diagrams were developed and discussed to explain the structural defects and band gap. As a conclusion it was found that the induced stress in the ZnO NSCs is the cause of gap narrowing between the energy levels. ZnO NWs and NRs showed homogeneous distribution of the Lowest Unoccupied Molecular Orbitals (LUMO) and Highest Occupied Molecular Orbitals (HOMO) orbitals all over the entire heterostructure which results to the reduction of the band gap. The calculated band gaps are confirmed to be in a good agreement with the experimental results. The electrical models and electrostatic potential maps were able to calculate the electron life time and to explain the mobility and diffusion behaviours of the grown nanostructures, respectively. 2016 Thesis NonPeerReviewed application/pdf en http://eprints.utm.my/id/eprint/92559/1/AmgadAhmedAliPMJIIT2016.pdf Ali Ibrahim, Amgad Ahmed (2016) Computational prosess design, optimization and growth of zinc oxide nanostructures on graphene by ultrasonic spray pyrolysis. PhD thesis, Universiti Teknologi Malaysia. http://dms.library.utm.my:8080/vital/access/manager/Repository/vital:106406
institution Universiti Teknologi Malaysia
building UTM Library
collection Institutional Repository
continent Asia
country Malaysia
content_provider Universiti Teknologi Malaysia
content_source UTM Institutional Repository
url_provider http://eprints.utm.my/
language English
topic T58.5-58.64 Information technology
spellingShingle T58.5-58.64 Information technology
Ali Ibrahim, Amgad Ahmed
Computational prosess design, optimization and growth of zinc oxide nanostructures on graphene by ultrasonic spray pyrolysis
description Computational process design, optimization, growth, characterization and computational analysis of zinc oxide (ZnO) nanostructures grown on graphene using zinc acetylacetonate (Zn(acac)2) in the presence of hydrogen by ultrasonic spray pyrolysis were performed systematically. The dissociation of Zn ions from vapour-phase Zn(acac)2 and its adsorption onto graphene oxide were studied using quantum mechanics approach involving the use of Density Functional Theory (DFT). The reaction energies were calculated, and the proposed reaction mechanism was well supported by a simulation of infrared properties. Next, Response Surface Methodology (RSM) was used to model and optimize the pyrolysis parameters by evaluating the nanostructure density, size and shape factor. The evolution of ZnO structures was well explained confirming that RSM is a reliable tool for the modelling and optimization of the pyrolysis parameters and prediction of nanostructure sizes and shapes. Finally, a computational analysis of the measured optical and charge transport properties of the grown nanostructures, i.e. Nanosphere Clusters (NSCs), Nanorods (NRs) and Nanowires (NWs) were developed. The calculated absorbance spectra based on the time-dependent DFT showed very close similarity with the measured behaviours. The atomic models and energy level diagrams were developed and discussed to explain the structural defects and band gap. As a conclusion it was found that the induced stress in the ZnO NSCs is the cause of gap narrowing between the energy levels. ZnO NWs and NRs showed homogeneous distribution of the Lowest Unoccupied Molecular Orbitals (LUMO) and Highest Occupied Molecular Orbitals (HOMO) orbitals all over the entire heterostructure which results to the reduction of the band gap. The calculated band gaps are confirmed to be in a good agreement with the experimental results. The electrical models and electrostatic potential maps were able to calculate the electron life time and to explain the mobility and diffusion behaviours of the grown nanostructures, respectively.
format Thesis
author Ali Ibrahim, Amgad Ahmed
author_facet Ali Ibrahim, Amgad Ahmed
author_sort Ali Ibrahim, Amgad Ahmed
title Computational prosess design, optimization and growth of zinc oxide nanostructures on graphene by ultrasonic spray pyrolysis
title_short Computational prosess design, optimization and growth of zinc oxide nanostructures on graphene by ultrasonic spray pyrolysis
title_full Computational prosess design, optimization and growth of zinc oxide nanostructures on graphene by ultrasonic spray pyrolysis
title_fullStr Computational prosess design, optimization and growth of zinc oxide nanostructures on graphene by ultrasonic spray pyrolysis
title_full_unstemmed Computational prosess design, optimization and growth of zinc oxide nanostructures on graphene by ultrasonic spray pyrolysis
title_sort computational prosess design, optimization and growth of zinc oxide nanostructures on graphene by ultrasonic spray pyrolysis
publishDate 2016
url http://eprints.utm.my/id/eprint/92559/1/AmgadAhmedAliPMJIIT2016.pdf
http://eprints.utm.my/id/eprint/92559/
http://dms.library.utm.my:8080/vital/access/manager/Repository/vital:106406
_version_ 1713199749644943360
score 13.211869

Similar Items