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The study of transparent hematite films using ultrafast and Raman spectroscopies
Dissertation (MSc (Physics))--University of Pretoria, 2019.
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| Format: | Thesis |
| Language: | English |
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University of Pretoria
2024
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| _version_ | 1867613599140151296 |
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| access_status_str | Open Access |
| author2 | Diale, M. (Mmantsae Moche) |
| author_browse | Diale, M. (Mmantsae Moche) |
| author_facet | Diale, M. (Mmantsae Moche) |
| collection | Thesis |
| dc_rights_str_mv | © 2021 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. |
| description | Dissertation (MSc (Physics))--University of Pretoria, 2019. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/97861 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:38:42.081Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2024 |
| publishDateRange | 2024 |
| publishDateSort | 2024 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/97861 The study of transparent hematite films using ultrafast and Raman spectroscopies Diale, M. (Mmantsae Moche) sipho.congolo@gmail.com Kruger, T.P.J. (Tjaart) Congolo, Sipho UCTD Hematite Spray pyrolysis Confocal Raman microscopy Pump-probe Transient absorption spectroscopy Dissertation (MSc (Physics))--University of Pretoria, 2019. Hematite (Fe2O3) is a promising photoanode material that is being studied immensely for its application in solar water splitting to produce hydrogen and oxygen as fuels. It has attractive properties such as a narrow bandgap that allows for absorption of visible light, it is earth-abundant and is an easily processable photocatalytic material. In this study, we report on hematite thin films prepared by spray pyrolysis on fluorine-doped tin oxide (FTO) coated glass substrates. The samples were prepared by spray pyrolysis and treated with tetraethoxysilane as well as post-annealed. We employed ultrafast transient absorption spectroscopy and high-resolution confocal Raman microscopy for analysis of the hematite thin films. For all the films, Raman spectroscopy confirmed the characteristic spectrum of the hematite. The high-resolution Raman mapping showed a uniform intensity over the analyzed areas which suggests a uniform coating of the hematite films on the FTO substrates. Ultrafast transient absorption spectroscopy was used to investigate the effect of three experimental parameters; the effect of the spray volume, tetraethoxysilicate treatment of the hematite and post-annealing at 500 ºC for 2 hours with 10 ºC/min ramping. All three parameters gave a positive result. Ultrafast transient absorption spectroscopy indicates that all three experimental parameters slowed down electron-hole recombination. Global analysis of the difference absorption data resolved the spectra and associated decay lifetimes of three distinct processes, operating on the ultrafast, tens of picoseconds and hundreds of picoseconds timescales. Thus, understanding these properties will aid in the engineering of this material to prolong recombination and, as a result, improve its solar to hydrogen conversion efficiency in photoelectrochemical cells. Physics MSc (Physics) Unrestricted Faculty of Natural and Agricultural Sciences 2024-08-26T12:32:17Z 2024-08-26T12:32:17Z 2020-04 2019-11 Dissertation * A2020 http://hdl.handle.net/2263/97861 en © 2021 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria |
| spellingShingle | UCTD Hematite Spray pyrolysis Confocal Raman microscopy Pump-probe Transient absorption spectroscopy The study of transparent hematite films using ultrafast and Raman spectroscopies |
| title | The study of transparent hematite films using ultrafast and Raman spectroscopies |
| title_full | The study of transparent hematite films using ultrafast and Raman spectroscopies |
| title_fullStr | The study of transparent hematite films using ultrafast and Raman spectroscopies |
| title_full_unstemmed | The study of transparent hematite films using ultrafast and Raman spectroscopies |
| title_short | The study of transparent hematite films using ultrafast and Raman spectroscopies |
| title_sort | study of transparent hematite films using ultrafast and raman spectroscopies |
| topic | UCTD Hematite Spray pyrolysis Confocal Raman microscopy Pump-probe Transient absorption spectroscopy |
| url | http://hdl.handle.net/2263/97861 |