Spectroscopic characterization and charging
Author(s)
Advisor
Süzer, ŞefikDate
2008Publisher
Bilkent University
Language
English
Type
ThesisItem Usage Stats
211
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58
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Abstract
The purpose of this work, is to investigate optical and electrical properties of
bimetallic alloy and core-shell Au and Ag nanoparticles by optical spectroscopy and
XPS, respectively. Several objectives have been pursued in achievement of the goals.
First goal is to investigate the tunability of optical properties of bimetallic Au and Ag
alloy and core-shell nanoparticles due to changes in composition and structure. The
second goal is to study the possibility of charge-storage on single metal particles,
especially on Au and Ag, and bimetallic alloy forms of the corresponding
nanoparticles in solution. Within this framework, bimetallic Au-Ag alloy and coreshell
particles are synthesized, then their electron-storage capacities in aqueous media
by introduction of sodium borohydride is followed by spectral shifts in their surface plasmon resonance bands. Moreover, the parameters like composition, structure,
affecting the charging ability of particles are reported by means of optical
spectroscopy as well. In addition, electron storing/releasing capacities of Au and Ag
nanoparticles and their kinetics are investigated.
In the second part, main focus is to investigate optical and electric properties
by surface modification through incorporating Au and Ag nanoparticles within
dielectric shell (silica and titania). Therefore, small Au@SiO2, Ag@SiO2, and
Ag@TiO2 core-shell nanoparticles with the metal core size ca. 5-7.5 nm and the shell
size ca. 3-7.5 nm are synthesized and optical properties of these nanoparticles are
studied. These nanoparticles are also analyzed by XPS under external biasing to get
further understanding of their charging capacities. Additionally, we investigated
incorporating metal nanoparticles within titania shell to provide enhanced
photoactivity through the metal core by means of increased charging capacity.
Keywords
Au-Ag Alloy NanoparticlesAu-Ag Core-Shell Nanoparticles
Electron Storing/Releasing
Surface Plasmon Resonance
Metal@Dielectric Core-Shell Nanoparticles
Charging/Discharging of Core-Shell Nanoparticles
XPS
Characterization of Core-Shell Nanoparticles
Permalink
http://hdl.handle.net/11693/14710Collections
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