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Plasmonic nanorods and nanoparticle-assemblies [Elektronische Ressource] : synthesis, characterization, and usage as sensors / Inga Zins

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Inga ZinsMainz, 2011Dissertationzur Erlangung des Grades“Doktor der Naturwissenschaften”im Promotionsfach Chemieam Fachbereich Chemie, Pharmazie und Geowissenschaftender Johannes Gutenberg-Universität MainzNanoChaNanopaSensodsrsPlasmonicracterization,roandandUsagerticle-AssembliesasSynthesis,Die vorliegende Arbeit wurde im Zeitraum von September 2007 bis Februar 2011 am Institut fürPhysikalische Chemie der Johannes Gutenberg-Universität Mainz angefertigt.Dekan:Erster Gutachter:ZweiterTag der mündlichen Prüfung: 16.03.2011IIIPlasmonic nanoparticles are subject to this study. They have the property that their interactionwith light results in a plasma-oscillation, visible in bright colors of the nanoparticle suspensions.The color of the particles depends on intrinstic (material, size, shape), as well as on externalfeatures (refractive index of the surrounding , distance of neighbouring nanoparticles). They aretherefore used as plasmonic sensors, reporting on changes in their environment. The demandfor sensing applications is not only a good sensitivity. The ability to reproducibly synthesizeplasmonic nanoparticles with designed features is important as well. Here, the growth of goldand silver-coated nanorods is studied, and the use of nanoparticles as orientation, refractive index,and distance sensor is explored.A model for the growth of gold nanords is developed.

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Published 01 January 2011
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Inga Zins
Mainz, 2011
Dissertation
zur Erlangung des Grades
“Doktor der Naturwissenschaften”
im Promotionsfach Chemie
am Fachbereich Chemie, Pharmazie und Geowissenschaften
der Johannes Gutenberg-Universität Mainz
NanoChaNanopaSensodsrsPlasmonicracterization,roandandUsagerticle-AssembliesasSynthesis,Die vorliegende Arbeit wurde im Zeitraum von September 2007 bis Februar 2011 am Institut für
Physikalische Chemie der Johannes Gutenberg-Universität Mainz angefertigt.
Dekan:
Erster Gutachter:
Zweiter
Tag der mündlichen Prüfung: 16.03.2011
IIIPlasmonic nanoparticles are subject to this study. They have the property that their interaction
with light results in a plasma-oscillation, visible in bright colors of the nanoparticle suspensions.
The color of the particles depends on intrinstic (material, size, shape), as well as on external
features (refractive index of the surrounding , distance of neighbouring nanoparticles). They are
therefore used as plasmonic sensors, reporting on changes in their environment. The demand
for sensing applications is not only a good sensitivity. The ability to reproducibly synthesize
plasmonic nanoparticles with designed features is important as well. Here, the growth of gold
and silver-coated nanorods is studied, and the use of nanoparticles as orientation, refractive index,
and distance sensor is explored.
A model for the growth of gold nanords is developed. It turns out that there are several factors,
which need to be fullfilled to do a succesful synthesis. Besides the presence of surfactant to stabi-
lize the growing particles, also bromide and silver are crucial, as well as a small electrochemical
potential difference between reducing and oxidizing reaction partners to allow for slow selective
anisotropic growth. Those gold nanorods are used to monitor the collapse of a gel matrix by
recording polarization-dependent time traces of their scattering intensity.
A chemical modification of the gold nanorods by a silver-shell increases the sample quality with
respect to the ensemble linewidth. The plasmonic focusing effect, a change in the slope of the
plasmon-shape-relation, is discovered. The easy optical monitoring allows to study the kinetics
of this reaction. Knowing reaction order and activation energy, the progress in the reaction is
forecast and the quenching time for a desired resonance wavelength is predicted.
Besides the application of single nanoparticles, also assemblies of them are probed. The
controlled arrangement of two particles of the same size is used to determine the interparticle
distance by different methods of calibration, including light-scattering and TEM-techniques.
The polarization of the scattered light along or perpendicular to the interparticle axis is used
to measure both, refractive index and interparticle distance, at once. Furthermore, the dimers
are a tool to characterize the behaviour of a thermoresponsive elastin-like linker-molecule upon
changes in the temperature and concentration. Core-satellite structures, consisting of a big core
particle surrounded by several smaller ones are used as refractive index sensor. It turns out that
they are better suited for refractive index sensing applications than pure spherical particles of the
same size, since their senistivity is much higher.
V
Abstract2.1. Spectra of Plasmonic Nanoparticles . . . . . . . . . . . . . . . . . . . . . . . 9
2.2. Localized Surface Plasmons . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.3. Rods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
2.4. Coated Nanoparticles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.5. Dimers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.5.1. Sensing with dimers . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
3.1. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
3.2. The Growth Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
3.2.1. Anisotropic Growth . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
3.2.2. High yield . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
3.2.3. Trends . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
3.3. Summary and Outlook . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
4.1. Plasmonic Focusing Effect . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
4.2. Kinetics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
5.1. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
5.2. Gold Nanorods in PNIPAM - Introducing the System . . . . . . . . . . . . . . 71
5.3. Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
5.4. Summary and Outlook . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
6.1. Dimers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
6.1.1. Calibrating the Plasmon Ruler . . . . . . . . . . . . . . . . . . . . . . 83
6.1.2. Distance and Refractive Index Sensor . . . . . . . . . . . . . . . . . . 85
6.1.3. Characterization of Elastin-Like Polypeptides . . . . . . . . . . . . . . 91
VII
NanoparyWhy2.GoldTheodsContents291.wth-MoIntroNovelductionRotating1Assemblies5.ro51fodsAroProbNano-GoldRoof6.Silver-Coatingrticle4.77esdsfoNanorrLodelcalGroViscositanisotropic?y3.699Contents
6.2. Core-Satellite Structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
6.2.1. Sensing Refractive Index Changes . . . . . . . . . . . . . . . . . . . . 98
6.2.2. Synthesis and Separation . . . . . . . . . . . . . . . . . . . . . . . . . 99
6.2.3. Summary and Outlook . . . . . . . . . . . . . . . . . . . . . . . . . . 101
A.1. Ensemble-Spectra . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
A.2. Single-Particle-Spectra . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
A.3. Dark-Field-Microscopy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
A.4. Electron-Microscopy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
A.5. Gel-Electrophoresis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
A.6. Dynamic Light Scattering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
B.1. FastSPS Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
B.2. Rotation Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
B.3. Polarization Contrast Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
C.1. General Synthesis of Gold Nanorods . . . . . . . . . . . . . . . . . . . . . . . 117
C.1.1. Overview Over the Carried out Syntheses . . . . . . . . . . . . . . . . 118
C.1.2. Spectra of the Carried out Syntheses . . . . . . . . . . . . . . . . . . 127
C.1.3. TEM-data of the Carried out . . . . . . . . . . . . . . . . . 134
C.1.4. Electrochemical Potential of the Growth Solution . . . . . . . . . . . . 142
C.2. Silver-Coating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147
C.3. Gold Nanorods in Gels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156
C.3.1. PNIPAM-Gels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156
C.3.2. Rotational Data Acquisition and Analysis . . . . . . . . . . . . . . . . 158
C.4. Biological Coatings (Bio-functionalization) . . . . . . . . . . . . . . . . . . . 165
C.4.1. Biotin-PEG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165
C.4.2. Streptavidin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165
C.4.3. ELP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166
C.4.4. Biotin-ELP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168
C.5. Dimers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174
C.5.1. Synthesis in Batch . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174
VIII
C.Summa1077.dsokSetupsOutloerimentalandDary115MrkeldAnalyticalExpA.Metho105117endixB.Appds103ethoC.5.2. Synthesis in the Flow-Cell . . . . . . . . . . . . . . . . . . . . . . . . 174
C.5.3. Sensing with Dimers . . . . . . . . . . . . . . . . . . . . . . . . . . . 176
C.5.4. TEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180
C.5.5. DLS of monomers . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184
C.6. Core-Satellite Assemblies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185
IX
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