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Title: Non-spherical plasmonic nanoparticles
Author: Wood, Christopher
ISNI:       0000 0004 6347 0878
Awarding Body: Imperial College London
Current Institution: Imperial College London
Date of Award: 2017
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The field of nanotechnology has grown exponentially in recent years. As advancements are made in synthetic technology, this allows for their implementation into new research areas, industries, and potential applications. Nanoparticles are an extensively studied area in nanotechnology, with a plethora of constituent materials providing a vast array of potential properties. Plasmonic nanoparticles in particular have the ability to absorb light, leading to enhancements in many applications, for example surface enhanced Raman spectroscopy. Many plasmonic nanoparticle studies are focused on spherical nanoparticles, but significantly less is known of their non-spherical counterparts. Non-spherical plasmonic nanoparticles possess unique optical and behavioural properties that are of significant technological interest. However, their relatively unknown formation mechanisms typically result in polydisperse samples and little being known of their specific behaviour. The work in this thesis is centred on three areas of non-spherical plasmonic nanoparticles. The first is based on silver nanoprisms, synthesised from the photo-conversion of silver seeds. A blue-shift of their dipole excitation after illumination was noted and investigated using UV-Vis and TEM. Nanoprism analogues were synthesised and investigated, including gold-coated, and hollowed prisms. The second area is based on the size-selection of silver nanoprism solutions using ultraconcentration through a liquid-liquid interface. These investigations were to determine whether such methods and which conditions could be used to increase monodispersity of such nanoparticle samples. An increase in mean size indicated a more monodispersed sample was achieved, and if progressed further could significantly improve the results of other sections or future research. The final section studies magnetic nanoparticles, and using magnetism to direct nanoparticles to points of interest on large multifunctional plasmonic substrates. Through these investigations, magnetic trapping was observed of single nanoparticles on pyramidal substrates.
Supervisor: Edel, Joshua ; Long, Nicholas Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral