The use of gold and silver nanoparticles has experienced a renaissance over the last 10 years and their number of uses in a variety of commercial products has dramatically increased. The first chapter of this thesis addresses the current and future uses of gold and silver nanoparticles, the methods employed in synthesising them and the theory behind their fascinating surface plasmon resonance properties. For the remainder of this thesis we will revisit one of the most common methods for growing gold nanoparticles, the Turkevich method, and then experimentally modify this method as our basis for growing gold nanoparticles in various ways. The second chapter deals with the slow decrease in average particle size observed in gold colloids grown by the Turkevich method where we establish why this occurs based on the nanoparticle formation mechanism. In the third chapter we investigate the effect of changing reagent concentration and activation method (thermal heating, microwave-assisted heating, ultra-violet light and sonication) on the average particle size. In the fourth chapter we investigate the effect of replacing the tri-sodium citrate reducing agent used in the Turkevich method with various ketones. In the fifth chapter we investigate how the Turkevich method can be used to grow primarily silver-gold core-shell particles a one-step and how these particles interact with methylene blue dye. In the sixth chapter we investigate a two-step route to gold-silver core-shell particles by employing gold “seeds” grown by the Turkevich method and the subsequent effect of using ascorbic acid as a co-reducing agent alongside tri-sodium citrate.
|Uppal, M. A.
|University College London (University of London)
|Electronic Thesis or Dissertation
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