LE3 .A278 2019

2019

Stamplecoskie, Kevin
Tong, Anthony

Acadia University

Bachelor of Science

Honours

Chemistry

Chemistry

Gold nanoclusters are an emerging class of materials that show great promise in a wide variety of analytical, catalytic, and biomedical applications due to their unique optical properties. They exhibit single-photon and multi-photon absorptions, fluorescence, as well as excellent catalytic reactivity. To achieve their full potential, specifically in catalysis, it is important to understand how size, geometry, and ligand choice influence their electrodynamics. A series of gold nanoclusters of various sizes (Au18–Au144) were prepared with thiolate protecting ligands. Raman spectroscopy was attempted on the most stable species of the clusters, Au25 (SC2H4Ph) 18. However, no peaks attributable to the nanocluster were observed. Femptosecond transient absorption spectroscopy was performed on each of the synthesized clusters and the kinetics of the excited-state relaxation were investigated. The majority of phenylethanethiolate-protected clusters exhibited a two-step relaxation decay, while the glutathionate-protected clusters exhibited a three-step decay, demonstrating the ligand effects on the excited-state dynamics of gold nanoclusters. Finally, parallel factor analysis was applied to excitation-emission matrices of binomial solutions of gold nanoclusters to develop a rapid technique to evaluate the monodispersity of nanocluster solutions. A qualitative, pass-fail, method of monodispersity evaluation was achieved, which could reduce the need for mass-spectrometry during cluster synthesis. The method also shows promise as a stand-alone evaluation of cluster solution monodispersity. However, more research is needed.

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https://scholar.acadiau.ca/islandora/object/theses:3306