Wang, Mingyue;
(2023)
Scalable production of bismuth-based materials for photo/electrochemical applications via aerosol-assisted chemical vapour deposition.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
This thesis is concerned with the film fabrication of bismuth-based semiconductors, including phenethylammonium bismuth iodide and bismuth oxyhalides, through aerosol-assisted chemical vapour deposition (AACVD) and the subsequent study of their applications, such as batteries, photoelectrochemical (PEC) water splitting and photocatalysis. Improvement of the films’ performance in the relative applications was achieved through the optimization of film structures and morphologies, heterojunction construction and doping. In Chapter 1, the fundamentals of AACVD and semiconductors is presented for the preliminary understanding of the technique and materials studied in this thesis. In addition, mechanisms and measurements of PEC water splitting and photocatalysis are discussed in order to understand the applications and performance of the investigated semiconductors. Chapter 2 explores the precursor synthesis and film deposition via AACVD of phenethylammonium bismuth iodide which is a low-toxicity alternative to lead-based perovskites. The effects of deposition parameters, annealing conditions and the type of substrates on the physical and chemical properties of the resultant films were studied thoroughly and discussed in this Chapter. In addition, the obtained films were applied successfully as the anode in aqueous Zn2+ electrolytes. In Chapter 3, the BiOI film deposited via AACVD was combined with a ZnO film to form a double-layer heterojunction for enhanced PEC activity. In both building structures, deposition temperatures and film thickness of the ZnO exhibited a strong influence on the performance of the heterojunctions. The mechanism behind the improved PEC performance and the stability of the obtained heterojunction were investigated in detail. Chapter 4 describes the significant improvement in visible-light photocatalysis of iodide-doped BiOBr films fabricated by AACVD. The modification of film properties such as growth orientations, morphologies and bandgaps induced by doping was analyzed systematically. The reasons behind the improved photocatalytic activity of iodide-doped BiOBr under visible-light irradiation were discussed as well. Chapter 5 provides a conclusion of the work included in this thesis and future outlook.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | Scalable production of bismuth-based materials for photo/electrochemical applications via aerosol-assisted chemical vapour deposition |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author 2023. Original content in this thesis is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) Licence (https://creativecommons.org/licenses/by-nc/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Chemistry |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10181463 |
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