Shan, Fengyuan;
(2024)
The photoresponse of gold nanostructures.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
The work outlined in this thesis gives an insight into two different types of gold nanostructures: spherical plasmonic gold nanoparticles (AuNPs), and Au25(cys)18 gold nanoclusters (NCs). A general introduction to gold nanoparticles and their unique property, localized surface plasmonic resonance, and gold nanoclusters and their electronic structures are provided in Chapter 1. Characterization methods for gold nanostructures for the research, and the experimental methods of the interaction between different kinds of gold nanoparticles and gold nanoclusters with cationic dyes are introduced in Chapter 2. In addition, femtosecond transient absorption spectroscopy with different pump and probe wavelengths was applied to investigate the relaxation dynamics following photoexcitation of Au25 clusters. The apparatus itself and the analysis process, are also detailed in this chapter. Chapter 3 of this thesis presents the interaction between anionic dyes (methylene blue and crystal violet) and different types and sizes of gold nanoparticles and gold nanoclusters, by monitoring UV-vis absorption spectroscopy, complemented by TEM imaging and DLS measuring to analyse the interaction. Chapter 4 reports on the use of transient absorption spectroscopy to analyse the relaxation dynamics of cysteine-protected Au25 nanoclusters under different pump wavelengths and solution with different polarities. The decay times of the excited states and as well as coherent oscillations provide a comprehensive picture of the electronic structure and dynamics of the Au25(cys)18. Overall, this thesis provides valuable new results on the photoresponse of different kinds of gold nanostructures with the help of UV-vis spectroscopy and femtosecond transient absorption spectroscopy. The research of the coherent oscillations and the relaxation dynamics upon the excitation gives a comprehensive understanding of Au25 nanoclusters. The result of this work is useful in the future studies of the Au25 nanoclusters and can find application in the work related in material science and in biochemistry.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | The photoresponse of gold nanostructures |
| 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.ucl.ac.uk/id/eprint/10192340 |
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